Concepts in Biochemical Pharmacology

Section Four: Methods of Studying the Metabolism of Drugs.- Subsection A. Assay of Drugs and Their Metabolites.- 22: Basic Principles in Development of Methods for Drug Assay. With 2 Figures.- A. Introduction.- B. Principles of Developing a Method.- I. Section of Method of Assay.- II. Choice of Solvent for Extraction of Drug.- III. Adsorption of Drugs by Glass Surfaces.- IV. Recoveries of Known Amounts of Compound from Biological Material.- V. Assessment of Sensitivity.- VI. Assessment of Specificity.- References.- 23: Absorption Spectrophotometry.- A. Ultraviolet Absorption Spectrophotometry.- I. Chromophores.- 1. Chromophore Coupling with Electron Fusing.- 2. Chromophore Coupling by a Saturated Link.- 3. Chromophore Coupling by Conjugated Systems.- 4. Effect of Tautomerism.- II. Environmental Influences.- 1. Effects of Solvent.- 2. Effects of Ionic Strength.- III. Applications of Ultraviolet Spectrophotometry to Drug Assay.- 1. Assays Based on a Change in pH.- 2. Assays Based on a Change of Redox State.- 3. Assays Based on Production of UV Absorption by Chemical Reaction.- 4. Blank Correction by Differential Wavelength Readings.- 5. Estimation of Drug and Metabolite at Differential Wavelengths.- B. Visible Absorption Spectrophotometry.- I. General.- II. Application of Visible Spectrophotometry to Drug Assay.- 1. Assays Based on Changes in pH.- 2. Assays Based on Changes of Redox State.- 3. Production of Visible Absorption by Chemical Reaction.- 4. Other Factors Affecting Visible Absorption.- C. Infrared Absorption Spectrophotometry.- References.- 24: Fluorometry. With 1 Figure.- A. Introduction.- B. Principles.- C. Practical Considerations.- I. Concentration.- II. Background Fluorescence.- III. Surface Adsorption of Fluorophors.- IV. Scattered Light.- D. Luminescence Analysis.- I. Types of Fluoroscence Assay Procedures.- II. Phosphorescence Analysis.- III. Application of Fluorescence Analysis to Drug Metabolism Studies.- IV. The Application of Fluorescence Spectroscopy to Drug Binding Studies.- References.- 25: Radioactive Techniques: The Use of Labeled Drugs. With 2 Figures.- A. Introduction.- B. Synthesis of Labeled Compounds.- I. Chemical Synthesis Procedures.- 1. Procedures for 3H.- 2. Procedures for 14C.- II. Biosynthesis Procedures.- 1. In Vivo Procedures.- 2. In Vitro Procedures.- C. Stability of Labeled Compounds.- D. Measurement of Labeled Drugs.- E. Specific Procedures for the Analysis of Labeled Compounds.- F. Use of Labeled Compounds to Study Drug Metabolism.- 6. Discussion of Basic Principles.- References.- 26: Radioactive Techniques: Radioactive Isotope Derivatives of Nonlabeled Drugs.- I. Estimation of Primary or Secondary Amines.- II. Estimation of Tertiary Amines.- III. Estimation of Drugs by Chelation.- IV. Estimation of Steroids as Radioactive Derivatives.- V. Enzymatic Production of Labeled Derivatives.- VI. Potential Applications of Radiolabeled Derivatizing Reagents.- References.- 27: Gas Chromatography. With 18 Figures.- I. Introduction.- II. Theory of Gas Chromatography.- III. Columns.- IV. Detectors.- V. Techniques in Gas Chromatography.- VI. Analytical Applications of Gas Chromatography in Pharmacology.- References.- 28: Enzymatic Assays in Pharmacology. With 4 Figures.- I. Introduction.- II. Enzymatic Assays with Pharmacological Agents as Substrates.- III. Enzymatic Assays with Drugs as Inhibitors.- IV. Competitive Protein Binding Analysis.- V. Conclusion.- References.- 29: Bioassay. With 2 Figures.- A. General Considerations.- I. Specificity.- II. Accuracy.- III. Automation.- B. Individual Assays.- I. Assays Used on Grounds of Sensitivity or Specificity.- II. Assays Used for Confirmation of Biological Activity (Steroids).- III. Assays Used because Chemical Methods are not yet Available.- IV. Proteins.- C. Conclusion.- References.- 30: Immunoassay. With 2 Figures.- References.- Subsection B. Isolation and Identification of Drug Metabolites.- 31: Paper, Column and Thin Layer Chromatography, Counter-Current Distribution and Electrophoresis..- A. Introduction.- B. Extraction from Tissues.- C. Counter-Current Distribution.- I. Theory.- II. Prediction of Separability.- III. Choice of Solvent Pairs for Counter-Current Distribution.- D. Chromatography.- I. The Properties of Adsorbents Used in Column Chromatography.- II. Liquid-Liquid Partition Chromatography.- III. Paper and Thin Layer Chromatography.- 1. Introduction.- 2. Paper Chromatography.- 3. Thin Layer Chromatography.- E. Electrophoresis.- References.- 32: Isotope Dilution Analysis. With 4 Figures.- A. Introduction.- B. Isotope Dilution Analysis.- 1. Direct Methods.- 2. Inverse Methods.- C. Modifications of Isotope Dilution Analysis.- D. Some Analytic Techniques Used in Conjunction with Radioassay Methods.- 1. Conversion of Samples to a Uniform Physical State.- 2. Addition and Purity of Carrier Material.- 3. Isolation of Drugs and Drug Metabolites.- 4. Purification of Isolated Material.- 5. Concentration and Radioactivity Measurements.- E. Applications of Isotopic Dilution Techniques.- 1. Examples of Direct Methods.- a) Pentobarbital.- b) Tolbutamide.- 2. Examples of Indirect Methods.- a) Warfarin.- b) Probenecid.- c) Fluroxene.- d) Folic Acid Antagonists.- e) Cyclophosphamide.- f) Thalidomide.- g) Tartrazine.- h) Benzene and Cyclohexane.- References.- 33: Gas Chromatography-Mass Spectrometry. With 8 Figures.- A. Introduction.- B. Operation of the Combined Gas Chromatograph-Mass Spectrometer.- C. Mass Spectral Fragmentation Processes.- D. Applications of Mass Spectrometry to the Problem of Identifying Drug Metabolites.- 1. Ethanol.- 2. Aspirin.- 3. Phenacetin.- 4. Tremorine.- 5. Siduron.- 6. Naphthalene.- 7. Probenecid.- 8. Brief Accounts of Mass Spectral Studies of Miscellaneous Compounds of Interest to Pharmacologists and Toxicologists.- a) Limonene.- b) Phytanic Acid.- c) Isoprene.- d) Acetylcholine.- e) The "Pink Spot" in Urine from Schizophrenics.- f) Bee Scent.- g) Trans-stilbene.- h) Pteridines.- i) Tetracycline.- j) Polychlorinated Biphenyls (PCB'Section Four: Methods of Studying the Metabolism of Drugs.- Subsection A. Assay of Drugs and Their Metabolites.- 22: Basic Principles in Development of Methods for Drug Assay. With 2 Figures.- A. Introduction.- B. Principles of Developing a Method.- I. Section of Method of Assay.- II. Choice of Solvent for Extraction of Drug.- III. Adsorption of Drugs by Glass Surfaces.- IV. Recoveries of Known Amounts of Compound from Biological Material.- V. Assessment of Sensitivity.- VI. Assessment of Specificity.- References.- 23: Absorption Spectrophotometry.- A. Ultraviolet Absorption Spectrophotometry.- I. Chromophores.- 1. Chromophore Coupling with Electron Fusing.- 2. Chromophore Coupling by a Saturated Link.- 3. Chromophore Coupling by Conjugated Systems.- 4. Effect of Tautomerism.- II. Environmental Influences.- 1. Effects of Solvent.- 2. Effects of Ionic Strength.- III. Applications of Ultraviolet Spectrophotometry to Drug Assay.- 1. Assays Based on a Change in pH.- 2. Assays Based on a Change of Redox State.- 3. Assays Based on Production of UV Absorption by Chemical Reaction.- 4. Blank Correction by Differential Wavelength Readings.- 5. Estimation of Drug and Metabolite at Differential Wavelengths.- B. Visible Absorption Spectrophotometry.- I. General.- II. Application of Visible Spectrophotometry to Drug Assay.- 1. Assays Based on Changes in pH.- 2. Assays Based on Changes of Redox State.- 3. Production of Visible Absorption by Chemical Reaction.- 4. Other Factors Affecting Visible Absorption.- C. Infrared Absorption Spectrophotometry.- References.- 24: Fluorometry. With 1 Figure.- A. Introduction.- B. Principles.- C. Practical Considerations.- I. Concentration.- II. Background Fluorescence.- III. Surface Adsorption of Fluorophors.- IV. Scattered Light.- D. Luminescence Analysis.- I. Types of Fluoroscence Assay Procedures.- II. Phosphorescence Analysis.- III. Application of Fluorescence Analysis to Drug Metabolism Studies.- IV. The Application of Fluorescence Spectroscopy to Drug Binding Studies.- References.- 25: Radioactive Techniques: The Use of Labeled Drugs. With 2 Figures.- A. Introduction.- B. Synthesis of Labeled Compounds.- I. Chemical Synthesis Procedures.- 1. Procedures for 3H.- 2. Procedures for 14C.- II. Biosynthesis Procedures.- 1. In Vivo Procedures.- 2. In Vitro Procedures.- C. Stability of Labeled Compounds.- D. Measurement of Labeled Drugs.- E. Specific Procedures for the Analysis of Labeled Compounds.- F. Use of Labeled Compounds to Study Drug Metabolism.- 6. Discussion of Basic Principles.- References.- 26: Radioactive Techniques: Radioactive Isotope Derivatives of Nonlabeled Drugs.- I. Estimation of Primary or Secondary Amines.- II. Estimation of Tertiary Amines.- III. Estimation of Drugs by Chelation.- IV. Estimation of Steroids as Radioactive Derivatives.- V. Enzymatic Production of Labeled Derivatives.- VI. Potential Applications of Radiolabeled Derivatizing Reagents.- References.- 27: Gas Chromatography. With 18 Figures.- I. Introduction.- II. Theory of Gas Chromatography.- III. Columns.- IV. Detectors.- V. Techniques in Gas Chromatography.- VI. Analytical Applications of Gas Chromatography in Pharmacology.- References.- 28: Enzymatic Assays in Pharmacology. With 4 Figures.- I. Introduction.- II. Enzymatic Assays with Pharmacological Agents as Substrates.- III. Enzymatic Assays with Drugs as Inhibitors.- IV. Competitive Protein Binding Analysis.- V. Conclusion.- References.- 29: Bioassay. With 2 Figures.- A. General Considerations.- I. Specificity.- II. Accuracy.- III. Automation.- B. Individual Assays.- I. Assays Used on Grounds of Sensitivity or Specificity.- II. Assays Used for Confirmation of Biological Activity (Steroids).- III. Assays Used because Chemical Methods are not yet Available.- IV. Proteins.- C. Conclusion.- References.- 30: Immunoassay. With 2 Figures.- References.- Subsection B. Isolation and Identification of Drug Metabolites.- 31: Paper, Column and Thin Layer Chromatography, Counter-Current Distribution and Electrophoresis..- A. Introduction.- B. Extraction from Tissues.- C. Counter-Current Distribution.- I. Theory.- II. Prediction of Separability.- III. Choice of Solvent Pairs for Counter-Current Distribution.- D. Chromatography.- I. The Properties of Adsorbents Used in Column Chromatography.- II. Liquid-Liquid Partition Chromatography.- III. Paper and Thin Layer Chromatography.- 1. Introduction.- 2. Paper Chromatography.- 3. Thin Layer Chromatography.- E. Electrophoresis.- References.- 32: Isotope Dilution Analysis. With 4 Figures.- A. Introduction.- B. Isotope Dilution Analysis.- 1. Direct Methods.- 2. Inverse Methods.- C. Modifications of Isotope Dilution Analysis.- D. Some Analytic Techniques Used in Conjunction with Radioassay Methods.- 1. Conversion of Samples to a Uniform Physical State.- 2. Addition and Purity of Carrier Material.- 3. Isolation of Drugs and Drug Metabolites.- 4. Purification of Isolated Material.- 5. Concentration and Radioactivity Measurements.- E. Applications of Isotopic Dilution Techniques.- 1. Examples of Direct Methods.- a) Pentobarbital.- b) Tolbutamide.- 2. Examples of Indirect Methods.- a) Warfarin.- b) Probenecid.- c) Fluroxene.- d) Folic Acid Antagonists.- e) Cyclophosphamide.- f) Thalidomide.- g) Tartrazine.- h) Benzene and Cyclohexane.- References.- 33: Gas Chromatography-Mass Spectrometry. With 8 Figures.- A. Introduction.- B. Operation of the Combined Gas Chromatograph-Mass Spectrometer.- C. Mass Spectral Fragmentation Processes.- D. Applications of Mass Spectrometry to the Problem of Identifying Drug Metabolites.- 1. Ethanol.- 2. Aspirin.- 3. Phenacetin.- 4. Tremorine.- 5. Siduron.- 6. Naphthalene.- 7. Probenecid.- 8. Brief Accounts of Mass Spectral Studies of Miscellaneous Compounds of Interest to Pharmacologists and Toxicologists.- a) Limonene.- b) Phytanic Acid.- c) Isoprene.- d) Acetylcholine.- e) The "Pink Spot" in Urine from Schizophrenics.- f) Bee Scent.- g) Trans-stilbene.- h) Pteridines.- i) Tetracycline.- j) Polychlorinated Biphenyls (PCB'Section Four: Methods of Studying the Metabolism of Drugs.- Subsection A. Assay of Drugs and Their Metabolites.- 22: Basic Principles in Development of Methods for Drug Assay. With 2 Figures.- A. Introduction.- B. Principles of Developing a Method.- I. Section of Method of Assay.- II. Choice of Solvent for Extraction of Drug.- III. Adsorption of Drugs by Glass Surfaces.- IV. Recoveries of Known Amounts of Compound from Biological Material.- V. Assessment of Sensitivity.- VI. Assessment of Specificity.- References.- 23: Absorption Spectrophotometry.- A. Ultraviolet Absorption Spectrophotometry.- I. Chromophores.- 1. Chromophore Coupling with Electron Fusing.- 2. Chromophore Coupling by a Saturated Link.- 3. Chromophore Coupling by Conjugated Systems.- 4. Effect of Tautomerism.- II. Environmental Influences.- 1. Effects of Solvent.- 2. Effects of Ionic Strength.- III. Applications of Ultraviolet Spectrophotometry to Drug Assay.- 1. Assays Based on a Change in pH.- 2. Assays Based on a Change of Redox State.- 3. Assays Based on Production of UV Absorption by Chemical Reaction.- 4. Blank Correction by Differential Wavelength Readings.- 5. Estimation of Drug and Metabolite at Differential Wavelengths.- B. Visible Absorption Spectrophotometry.- I. General.- II. Application of Visible Spectrophotometry to Drug Assay.- 1. Assays Based on Changes in pH.- 2. Assays Based on Changes of Redox State.- 3. Production of Visible Absorption by Chemical Reaction.- 4. Other Factors Affecting Visible Absorption.- C. Infrared Absorption Spectrophotometry.- References.- 24: Fluorometry. With 1 Figure.- A. Introduction.- B. Principles.- C. Practical Considerations.- I. Concentration.- II. Background Fluorescence.- III. Surface Adsorption of Fluorophors.- IV. Scattered Light.- D. Luminescence Analysis.- I. Types of Fluoroscence Assay Procedures.- II. Phosphorescence Analysis.- III. Application of Fluorescence Analysis to Drug Metabolism Studies.- IV. The Application of Fluorescence Spectroscopy to Drug Binding Studies.- References.- 25: Radioactive Techniques: The Use of Labeled Drugs. With 2 Figures.- A. Introduction.- B. Synthesis of Labeled Compounds.- I. Chemical Synthesis Procedures.- 1. Procedures for 3H.- 2. Procedures for 14C.- II. Biosynthesis Procedures.- 1. In Vivo Procedures.- 2. In Vitro Procedures.- C. Stability of Labeled Compounds.- D. Measurement of Labeled Drugs.- E. Specific Procedures for the Analysis of Labeled Compounds.- F. Use of Labeled Compounds to Study Drug Metabolism.- 6. Discussion of Basic Principles.- References.- 26: Radioactive Techniques: Radioactive Isotope Derivatives of Nonlabeled Drugs.- I. Estimation of Primary or Secondary Amines.- II. Estimation of Tertiary Amines.- III. Estimation of Drugs by Chelation.- IV. Estimation of Steroids as Radioactive Derivatives.- V. Enzymatic Production of Labeled Derivatives.- VI. Potential Applications of Radiolabeled Derivatizing Reagents.- References.- 27: Gas Chromatography. With 18 Figures.- I. Introduction.- II. Theory of Gas Chromatography.- III. Columns.- IV. Detectors.- V. Techniques in Gas Chromatography.- VI. Analytical Applications of Gas Chromatography in Pharmacology.- References.- 28: Enzymatic Assays in Pharmacology. With 4 Figures.- I. Introduction.- II. Enzymatic Assays with Pharmacological Agents as Substrates.- III. Enzymatic Assays with Drugs as Inhibitors.- IV. Competitive Protein Binding Analysis.- V. Conclusion.- References.- 29: Bioassay. With 2 Figures.- A. General Considerations.- I. Specificity.- II. Accuracy.- III. Automation.- B. Individual Assays.- I. Assays Used on Grounds of Sensitivity or Specificity.- II. Assays Used for Confirmation of Biological Activity (Steroids).- III. Assays Used because Chemical Methods are not yet Available.- IV. Proteins.- C. Conclusion.- References.- 30: Immunoassay. With 2 Figures.- References.- Subsection B. Isolation and Identification of Drug Metabolites.- 31: Paper, Column and Thin Layer Chromatography, Counter-Current Distribution and Electrophoresis..- A. Introduction.- B. Extraction from Tissues.- C. Counter-Current Distribution.- I. Theory.- II. Prediction of Separability.- III. Choice of Solvent Pairs for Counter-Current Distribution.- D. Chromatography.- I. The Properties of Adsorbents Used in Column Chromatography.- II. Liquid-Liquid Partition Chromatography.- III. Paper and Thin Layer Chromatography.- 1. Introduction.- 2. Paper Chromatography.- 3. Thin Layer Chromatography.- E. Electrophoresis.- References.- 32: Isotope Dilution Analysis. With 4 Figures.- A. Introduction.- B. Isotope Dilution Analysis.- 1. Direct Methods.- 2. Inverse Methods.- C. Modifications of Isotope Dilution Analysis.- D. Some Analytic Techniques Used in Conjunction with Radioassay Methods.- 1. Conversion of Samples to a Uniform Physical State.- 2. Addition and Purity of Carrier Material.- 3. Isolation of Drugs and Drug Metabolites.- 4. Purification of Isolated Material.- 5. Concentration and Radioactivity Measurements.- E. Applications of Isotopic Dilution Techniques.- 1. Examples of Direct Methods.- a) Pentobarbital.- b) Tolbutamide.- 2. Examples of Indirect Methods.- a) Warfarin.- b) Probenecid.- c) Fluroxene.- d) Folic Acid Antagonists.- e) Cyclophosphamide.- f) Thalidomide.- g) Tartrazine.- h) Benzene and Cyclohexane.- References.- 33: Gas Chromatography-Mass Spectrometry. With 8 Figures.- A. Introduction.- B. Operation of the Combined Gas Chromatograph-Mass Spectrometer.- C. Mass Spectral Fragmentation Processes.- D. Applications of Mass Spectrometry to the Problem of Identifying Drug Metabolites.- 1. Ethanol.- 2. Aspirin.- 3. Phenacetin.- 4. Tremorine.- 5. Siduron.- 6. Naphthalene.- 7. Probenecid.- 8. Brief Accounts of Mass Spectral Studies of Miscellaneous Compounds of Interest to Pharmacologists and Toxicologists.- a) Limonene.- b) Phytanic Acid.- c) Isoprene.- d) Acetylcholine.- e) The "Pink Spot" in Urine from Schizophrenics.- f) Bee Scent.- g) Trans-stilbene.- h) Pteridines.- i) Tetracycline.- j) Polychlorinated Biphenyls (PCB's).- k) DDT.- E. Forensic Applications.- References.- 34: The Application of Various Spectroscopies to the Identification of Drug Metabolites. With 5 Figures.- A. Introduction.- B. Sample Requirements and Isolation Procedures.- C. Mass Spectrometry.- D. Nuclear Magnetic Resonance Spectroscopy.- E. Infrared Spectroscopy.- F. Ultraviolet Spectroscopy.- G. Optical Rotatory Dispersion and Circular Dichroism.- H. Diazepam Metabolites.- J. Triprolidine Metabolites.- References.- Section Five: Sites of Drug Metabolism.- 35: Introduction: Pathways of Drug Metabolism.- A. The Biphasic Metabolism of Drugs.- B. Phase I Reactions.- I. Oxidative Reactions.- 1. The Oxidation of Aromatic Rings.- 2. The Oxidation of Alkyl Chains.- 3. Oxidative Dealkylation.- 4. N-Oxidation.- 5. Sulphoxidation.- 6. Replacement of S by O.- 7. Epoxidation.- II. Reductions.- III. Hydrolyses.- C. Conjugations or Phase II Reactions.- I. Types of Conjugation Reactions.- 1. Glucuronic Acid Conjugation.- 2. Glucoside Conjugation.- 3. Hippuric Acid Synthesis.- 4. Mercapturic Acid Synthesis.- 5. Ornithuric Acid Synthesis.- 6. Glutamine Conjugation.- 7. Ethereal Sulphate Synthesis.- 8. The Cyanide Detoxication.- 9. Methylation.- 10. Acetylation.- II. Mechanism of Conjugation.- D. Compounds which are not Metabolized.- E. Spontaneous Reactions.- F. The Excretion of Foreign Compounds.- References.- Subsection A: Microsomal Enzymes.- 36: Some Morphological Characteristics of Hepatocyte Endoplasmic Reticulum and Some Relationships between Endoplasmic Reticulum, Microsomes, and Drug Metabolism.- I. Some Morphological Considerations.- II. Some Structure-activity Correlations.- III. Some Problems in Correlating ER Structure and Microsomal Enzyme Activity.- IV. Localization of Drug Metabolizing Enzymes in Submicrosomal Fractions.- References.- 37: Model Systems in Studies of the Chemistry and the Enzymatic Activation of Oxygen. With 9 Figures.- A. Introduction.- B. Chemical Properties of the Active Oxygen in Enzymatic Monooxygenations.- I. Hydroxylations of Aliphatic CH-Bonds.- II. Monooxygenation of the Isolated Double Bond.- III. Monooxygenation of Aromatic Systems.- IV. Monooxygenation at Heteroatoms.- C. Model Reactions for the Enzymatic Active Oxygen.- D. Model Systems for Oxygen Activation by Monooxygenases.- References.- 38: Cytochrome P-450 -#8217;s).- k) DDT.- E. Forensic Applications.- References.- 34: The Application of Various Spectroscopies to the Identification of Drug Metabolites. With 5 Figures.- A. Introduction.- B. Sample Requirements and Isolation Procedures.- C. Mass Spectrometry.- D. Nuclear Magnetic Resonance Spectroscopy.- E. Infrared Spectroscopy.- F. Ultraviolet Spectroscopy.- G. Optical Rotatory Dispersion and Circular Dichroism.- H. Diazepam Metabolites.- J. Triprolidine Metabolites.- References.- Section Five: Sites of Drug Metabolism.- 35: Introduction: Pathways of Drug Metabolism.- A. The Biphasic Metabolism of Drugs.- B. Phase I Reactions.- I. Oxidative Reactions.- 1. The Oxidation of Aromatic Rings.- 2. The Oxidation of Alkyl Chains.- 3. Oxidative Dealkylation.- 4. N-Oxidation.- 5. Sulphoxidation.- 6. Replacement of S by O.- 7. Epoxidation.- II. Reductions.- III. Hydrolyses.- C. Conjugations or Phase II Reactions.- I. Types of Conjugation Reactions.- 1. Glucuronic Acid Conjugation.- 2. Glucoside Conjugation.- 3. Hippuric Acid Synthesis.- 4. Mercapturic Acid Synthesis.- 5. Ornithuric Acid Synthesis.- 6. Glutamine Conjugation.- 7. Ethereal Sulphate Synthesis.- 8. The Cyanide Detoxication.- 9. Methylation.- 10. Acetylation.- II. Mechanism of Conjugation.- D. Compounds which are not Metabolized.- E. Spontaneous Reactions.- F. The Excretion of Foreign Compounds.- References.- Subsection A: Microsomal Enzymes.- 36: Some Morphological Characteristics of Hepatocyte Endoplasmic Reticulum and Some Relationships between Endoplasmic Reticulum, Microsomes, and Drug Metabolism.- I. Some Morphological Considerations.- II. Some Structure-activity Correlations.- III. Some Problems in Correlating ER Structure and Microsomal Enzyme Activity.- IV. Localization of Drug Metabolizing Enzymes in Submicrosomal Fractions.- References.- 37: Model Systems in Studies of the Chemistry and the Enzymatic Activation of Oxygen. With 9 Figures.- A. Introduction.- B. Chemical Properties of the Active Oxygen in Enzymatic Monooxygenations.- I. Hydroxylations of Aliphatic CH-Bonds.- II. Monooxygenation of the Isolated Double Bond.- III. Monooxygenation of Aromatic Systems.- IV. Monooxygenation at Heteroatoms.- C. Model Reactions for the Enzymatic Active Oxygen.- D. Model Systems for Oxygen Activation by Monooxygenases.- References.- 38: Cytochrome P-450 -Section Four: Methods of Studying the Metabolism of Drugs.- Subsection A. Assay of Drugs and Their Metabolites.- 22: Basic Principles in Development of Methods for Drug Assay. With 2 Figures.- A. Introduction.- B. Principles of Developing a Method.- I. Section of Method of Assay.- II. Choice of Solvent for Extraction of Drug.- III. Adsorption of Drugs by Glass Surfaces.- IV. Recoveries of Known Amounts of Compound from Biological Material.- V. Assessment of Sensitivity.- VI. Assessment of Specificity.- References.- 23: Absorption Spectrophotometry.- A. Ultraviolet Absorption Spectrophotometry.- I. Chromophores.- 1. Chromophore Coupling with Electron Fusing.- 2. Chromophore Coupling by a Saturated Link.- 3. Chromophore Coupling by Conjugated Systems.- 4. Effect of Tautomerism.- II. Environmental Influences.- 1. Effects of Solvent.- 2. Effects of Ionic Strength.- III. Applications of Ultraviolet Spectrophotometry to Drug Assay.- 1. Assays Based on a Change in pH.- 2. Assays Based on a Change of Redox State.- 3. Assays Based on Production of UV Absorption by Chemical Reaction.- 4. Blank Correction by Differential Wavelength Readings.- 5. Estimation of Drug and Metabolite at Differential Wavelengths.- B. Visible Absorption Spectrophotometry.- I. General.- II. Application of Visible Spectrophotometry to Drug Assay.- 1. Assays Based on Changes in pH.- 2. Assays Based on Changes of Redox State.- 3. Production of Visible Absorption by Chemical Reaction.- 4. Other Factors Affecting Visible Absorption.- C. Infrared Absorption Spectrophotometry.- References.- 24: Fluorometry. With 1 Figure.- A. Introduction.- B. Principles.- C. Practical Considerations.- I. Concentration.- II. Background Fluorescence.- III. Surface Adsorption of Fluorophors.- IV. Scattered Light.- D. Luminescence Analysis.- I. Types of Fluoroscence Assay Procedures.- II. Phosphorescence Analysis.- III. Application of Fluorescence Analysis to Drug Metabolism Studies.- IV. The Application of Fluorescence Spectroscopy to Drug Binding Studies.- References.- 25: Radioactive Techniques: The Use of Labeled Drugs. With 2 Figures.- A. Introduction.- B. Synthesis of Labeled Compounds.- I. Chemical Synthesis Procedures.- 1. Procedures for 3H.- 2. Procedures for 14C.- II. Biosynthesis Procedures.- 1. In Vivo Procedures.- 2. In Vitro Procedures.- C. Stability of Labeled Compounds.- D. Measurement of Labeled Drugs.- E. Specific Procedures for the Analysis of Labeled Compounds.- F. Use of Labeled Compounds to Study Drug Metabolism.- 6. Discussion of Basic Principles.- References.- 26: Radioactive Techniques: Radioactive Isotope Derivatives of Nonlabeled Drugs.- I. Estimation of Primary or Secondary Amines.- II. Estimation of Tertiary Amines.- III. Estimation of Drugs by Chelation.- IV. Estimation of Steroids as Radioactive Derivatives.- V. Enzymatic Production of Labeled Derivatives.- VI. Potential Applications of Radiolabeled Derivatizing Reagents.- References.- 27: Gas Chromatography. With 18 Figures.- I. Introduction.- II. Theory of Gas Chromatography.- III. Columns.- IV. Detectors.- V. Techniques in Gas Chromatography.- VI. Analytical Applications of Gas Chromatography in Pharmacology.- References.- 28: Enzymatic Assays in Pharmacology. With 4 Figures.- I. Introduction.- II. Enzymatic Assays with Pharmacological Agents as Substrates.- III. Enzymatic Assays with Drugs as Inhibitors.- IV. Competitive Protein Binding Analysis.- V. Conclusion.- References.- 29: Bioassay. With 2 Figures.- A. General Considerations.- I. Specificity.- II. Accuracy.- III. Automation.- B. Individual Assays.- I. Assays Used on Grounds of Sensitivity or Specificity.- II. Assays Used for Confirmation of Biological Activity (Steroids).- III. Assays Used because Chemical Methods are not yet Available.- IV. Proteins.- C. Conclusion.- References.- 30: Immunoassay. With 2 Figures.- References.- Subsection B. Isolation and Identification of Drug Metabolites.- 31: Paper, Column and Thin Layer Chromatography, Counter-Current Distribution and Electrophoresis..- A. Introduction.- B. Extraction from Tissues.- C. Counter-Current Distribution.- I. Theory.- II. Prediction of Separability.- III. Choice of Solvent Pairs for Counter-Current Distribution.- D. Chromatography.- I. The Properties of Adsorbents Used in Column Chromatography.- II. Liquid-Liquid Partition Chromatography.- III. Paper and Thin Layer Chromatography.- 1. Introduction.- 2. Paper Chromatography.- 3. Thin Layer Chromatography.- E. Electrophoresis.- References.- 32: Isotope Dilution Analysis. With 4 Figures.- A. Introduction.- B. Isotope Dilution Analysis.- 1. Direct Methods.- 2. Inverse Methods.- C. Modifications of Isotope Dilution Analysis.- D. Some Analytic Techniques Used in Conjunction with Radioassay Methods.- 1. Conversion of Samples to a Uniform Physical State.- 2. Addition and Purity of Carrier Material.- 3. Isolation of Drugs and Drug Metabolites.- 4. Purification of Isolated Material.- 5. Concentration and Radioactivity Measurements.- E. Applications of Isotopic Dilution Techniques.- 1. Examples of Direct Methods.- a) Pentobarbital.- b) Tolbutamide.- 2. Examples of Indirect Methods.- a) Warfarin.- b) Probenecid.- c) Fluroxene.- d) Folic Acid Antagonists.- e) Cyclophosphamide.- f) Thalidomide.- g) Tartrazine.- h) Benzene and Cyclohexane.- References.- 33: Gas Chromatography-Mass Spectrometry. With 8 Figures.- A. Introduction.- B. Operation of the Combined Gas Chromatograph-Mass Spectrometer.- C. Mass Spectral Fragmentation Processes.- D. Applications of Mass Spectrometry to the Problem of Identifying Drug Metabolites.- 1. Ethanol.- 2. Aspirin.- 3. Phenacetin.- 4. Tremorine.- 5. Siduron.- 6. Naphthalene.- 7. Probenecid.- 8. Brief Accounts of Mass Spectral Studies of Miscellaneous Compounds of Interest to Pharmacologists and Toxicologists.- a) Limonene.- b) Phytanic Acid.- c) Isoprene.- d) Acetylcholine.- e) The "Pink Spot" in Urine from Schizophrenics.- f) Bee Scent.- g) Trans-stilbene.- h) Pteridines.- i) Tetracycline.- j) Polychlorinated Biphenyls (PCB's).- k) DDT.- E. Forensic Applications.- References.- 34: The Application of Various Spectroscopies to the Identification of Drug Metabolites. With 5 Figures.- A. Introduction.- B. Sample Requirements and Isolation Procedures.- C. Mass Spectrometry.- D. Nuclear Magnetic Resonance Spectroscopy.- E. Infrared Spectroscopy.- F. Ultraviolet Spectroscopy.- G. Optical Rotatory Dispersion and Circular Dichroism.- H. Diazepam Metabolites.- J. Triprolidine Metabolites.- References.- Section Five: Sites of Drug Metabolism.- 35: Introduction: Pathways of Drug Metabolism.- A. The Biphasic Metabolism of Drugs.- B. Phase I Reactions.- I. Oxidative Reactions.- 1. The Oxidation of Aromatic Rings.- 2. The Oxidation of Alkyl Chains.- 3. Oxidative Dealkylation.- 4. N-Oxidation.- 5. Sulphoxidation.- 6. Replacement of S by O.- 7. Epoxidation.- II. Reductions.- III. Hydrolyses.- C. Conjugations or Phase II Reactions.- I. Types of Conjugation Reactions.- 1. Glucuronic Acid Conjugation.- 2. Glucoside Conjugation.- 3. Hippuric Acid Synthesis.- 4. Mercapturic Acid Synthesis.- 5. Ornithuric Acid Synthesis.- 6. Glutamine Conjugation.- 7. Ethereal Sulphate Synthesis.- 8. The Cyanide Detoxication.- 9. Methylation.- 10. Acetylation.- II. Mechanism of Conjugation.- D. Compounds which are not Metabolized.- E. Spontaneous Reactions.- F. The Excretion of Foreign Compounds.- References.- Subsection A: Microsomal Enzymes.- 36: Some Morphological Characteristics of Hepatocyte Endoplasmic Reticulum and Some Relationships between Endoplasmic Reticulum, Microsomes, and Drug Metabolism.- I. Some Morphological Considerations.- II. Some Structure-activity Correlations.- III. Some Problems in Correlating ER Structure and Microsomal Enzyme Activity.- IV. Localization of Drug Metabolizing Enzymes in Submicrosomal Fractions.- References.- 37: Model Systems in Studies of the Chemistry and the Enzymatic Activation of Oxygen. With 9 Figures.- A. Introduction.- B. Chemical Properties of the Active Oxygen in Enzymatic Monooxygenations.- I. Hydroxylations of Aliphatic CH-Bonds.- II. Monooxygenation of the Isolated Double Bond.- III. Monooxygenation of Aromatic Systems.- IV. Monooxygenation at Heteroatoms.- C. Model Reactions for the Enzymatic Active Oxygen.- D. Model Systems for Oxygen Activation by Monooxygenases.- References.- 38: Cytochrome P-450 - Its Function in the Oxidative Metabolism of Drugs. With 23 Figures.- I. Discovery of Cytochrome P-450.- II. Function of Cytochrome P-450.- III. How Does Cytochrome P-450 Function ?.- IV. Cytochrome P-450: Monomorphous or Polymorphous?.- V. The Enzymatic Reduction of Cytochrome P-450.- VI. The Organization of the Microsomal Electron Transport Chain.- Summary.- Addendum.- References.- 39: Enzymatic Oxidation at Carbon.- A. Introduction.- B. Aliphatic Hydroxylation.- I. Hydroxylation at the Terminal Methyl Group.- II. Hydroxylation at the Penultimate Methylene Group.- III. Hydroxylation at the Benzylic Position.- IV. Hydroxylation at the Allylic Position.- V. Hydroxylation of Alicyclic Rings.- VI. Hydroxylation at Carbon ?- to a Heteroatom.- VII. Hydroxylation at Carbon ?- or ?- to a Carbonyl Group.- VIII. Mechanistic Studies.- C. Peroxidation.- D. Epoxidation.- I. Epoxidation of Conjugated and Unconjugated Olefins.- II. Epoxidation of Aromatic Double Bonds.- III. Epoxide Hydrase.- E. Aromatic Oxidation.- I. Hydroxylation of Substituted Benzenes.- II. Hydroxylation of Bicyclic and Polycyclic Aromatic Compounds.- III. The NIH Shift.- IV. Arene Oxides.- F. Summary.- References.- 40: N-Oxidation Enzymes. With 2 Figures.- I. Introduction.- II. N-Hydroxylation in Vitro.- III. Formation of N-Hydroxy Derivatives by Biochemical Reduction.- IV. Formation and Reactions of Tertiary Amine and Heterocyclic N-Oxides.- V. Conclusions.- References.- 41: Enzymatic N-, 0-, and S-Dealkylation of Foreign Compounds by Hepatic Microsomes. With 4 Figures.- A. N-Dealkylation.- I. Relationship of the N-Alkyl Substituent to the Rate of Dealkylation.- II. Relative Rates of N-Dealkylation of Secondary and Tertiary Amines.- 1. In Vivo.- 2. In Vitro.- III. Multiple Microsomal N-Demethylases.- IV. Mechanism of Microsomal N-Dealkylation.- 1. Cytochrome P-450.- 2. N-Oxide Formation.- 3. Isotope Effects on Microsomal Dealkylation.- V. Stereospecificity in N-Dealkylation.- VI. Fate of Aldehydes Formed during Metabolic Dealkylation of Drugs.- B. O-Dealkylation.- I. Relationship of the O-Alkyl Substituent to the Rate of Dealkylation.- II. Mechanism of Microsomal O-Dealkylation.- C. S-Dealkylation.- D. Summary.- References.- 42: Reductive Enzymes. With 6 Figures.- A. Introduction.- B. Reduction of Nitro Compounds.- I. Enzymatic Mechanisms in Liver.- II. Enzymatic Reduction of Nitro Compounds in Other Mammalian Tissues.- III. Nitro Reduction by Bacterial Enzymes.- IV. Semi-nonenzymatic Reactions.- C. Azo Reduction.- I. Azo Reduction in Liver.- II. Semi-nonenzymatic Reactions.- III. Azo Reduction in Other Mammalian Tissues.- IV. Bacterial Enzymes.- V. Relative Importance of Azo Reductases.- References.- 43: Oxidative Desulfuration and Dearylation of Selected Organophosphate Insecticides.- References.- 44: Metabolism of Halogenated Compounds. With 7 Figures.- I. General Consideration of the Halogen-Carbon Bond.- 1. Chemical Reactivity of Aromatic Halogen Derivatives.- 2. Chemical Reactivity of Aliphatic Halogen Derivatives.- II. Metabolism of Halogenated Aromatic Hydrocarbons.- III. Metabolism of Aliphatic Halogenated Compounds.- IV. Indirect Tests of Dehalogenation.- V. Dehalogenation of Insecticides.- Summary and Conclusions.- References.- 45: Glucuronide-Forming Enzymes. With 1 Figure.- A. Mechanism of Glucuronide Biosynthesis.- I. Transference from Uridine Diphosphate Glucuronic Acid.- II. Other Enzymic Pathways of Glucuronide Biosynthesis.- III. Non-Enzymic Pathways of Glucuronide Biosynthesis.- IV. Study of Glucuronide Biosynthesis.- B. UDPGlucuronic Acid.- C. UDPGlucuronyltransferase.- I. Occurence of UDPGlucuronyltransferase in Species.- II. Occurence of UDPGlucuronyltransferase in Tissues.- III. Location of UDPGlucuronyltransferase in the Cell.- IV. Purification of UDPGlucuronyltransferase.- V. Catalytic Center.- VI. Specificity of UDPGlucuronyltransferase.- VII. Factors Affecting Observed UDPGlucuronyltransferase Activity in Vitro.- D. Factors Affecting Overall Glucuronidation in Vivo.- I. Age.- II. Diet.- III. Hormones.- IV. Genetic Factors.- V. Administration of Drugs and Steroids.- VI. Environmental Factors.- VII. Toxicological and Pathological Factors.- References.- 46: Metabolism of Normal Body Constituents by Drug-Metabolizing Enzymes in Liver Microsomes.- A. Introduction.- B. Steroid Hormones.- I. Factors Influencing Steroid Hydroxylation.- II. Effect of Enzyme Induction on Steroid Action.- III. Effect of Enzyme Induction on Steroid Hydroxylation in Man.- C. Cholesterol.- I. Biosynthesis.- II. Metabolism to Bile Acids.- D. Fatty Acids.- I. ?-Oxidation.- II. Desaturation.- E. Thyroxin.- F. Bilirubin.- G. Miscellaneous.- I. Indoles.- II. Sympathomimetic Amines.- III. Heme.- IV. Kynurenine and Anthranilic Acid.- V. Methylated Purines.- H. Concluding Remarks.- References.- 47: Tissue Distribution Studies of Polycyclic Hydrocarbon Hydroxylase Activity.- I. Introduction.- II. Histochemical Studies of Polycyclic Hydrocarbon Hydroxylase Systems.- III. Quantitative Studies of Polycyclic Hydrocarbon Hydroxylase Systems.- IV. Implications of Extra-Hepatic Distribution of Drug Metabolizing Systems.- References.- 48: Mechanisms of Induction of Drug Metabolism Enzymes. With 9 Figures.- A. Introduction.- B. Effects of Polycyclic Hydrocarbons and Phenobarbital on Protein Synthesis.- C. Enzyme Induction and the Gene-Action System.- D. Effect of Inducers on the Turnover and Activity of Microsomal Proteins.- E. Effects of Inhibitors on the Induction of Enzyme Activities in Vivo.- I. Enzyme Induction in Vivo.- II. Enzyme Induction in Isolated Perfused Rat Liver.- F. Enzyme Induction in Cell Culture.- I. Estimation of Half-Life of Induced Aryl Hydroxylase Activity.- II. Effects of Metabolic Inhibitors on Inducible Aryl Hydroxylase.- III. A Translation-independent Phase of Aryl Hydrocarbon Hydroxylase Induction.- G. The Effect of Inducers on RNA Metabolism.- References.- 49: Inhibition of Drug Metabolism. With 1 Figure.- A. Methods of Determining Inhibition of Drug Metabolism.- I. In Vivo Methods.- II. In Vitro Methods.- III. Combined in Vivo-in Vitro Methods.- B. Implication of a Common Drug Metabolizing System.- C. Inhibition of the Metabolism of One Drug by Another Drug in Vivo.- D. SKF 525-A and other Prolonging Agents.- E. Role of Binding of Inhibitors to Cytochrome P-450.- F. Some Applications of Inhibitors.- G. Therapeutic Implications of Inhibition of Drug Metabolism.- References.- Subsection B: Nonmicrosomal Enzymes.- 50: Esterases of Human Tissues. With 2 Figures.- A. Introduction.- B. Properties of Different Types of Esterases.- C. Blood Esterases.- 1. Serum Esterases.- 2. Erythrocyte Esterases.- D. Tissue Esterases.- 1. Liver.- 2. Kidney.- 3. Skeletal and Smooth Muscle.- 4. Brain.- 5. Esterases of Other Human Tissues.- E. Hydrolysis of Drugs Containing Ester Groups in Man.- Summary.- References.- 51: Enzymatic Oxidation and Reduction of Alcohols, Aldehydes and Ketones.- A. Oxido-Reductases.- I. Liver Alcohol Dehydrogenase.- 1. General Properties.- 2. Substrate Selectivity of LADH.- 3. Stereochemistry and Mechanism.- II. Other Alcohol Dehydrogenases.- III. Reductases.- 1. 4-Ketoproline Reductase.- 2. Aromatic Aldehyde-Ketone Reductase.- 3. Pig Liver Reductase.- 4. ?-?-Unsaturated Ketone Reductase.- 5. Kidney Lactaldehyde Reductase.- 6. Retinal Reductase from Rat Intestine.- 7. Aromatic ?-Keto Acid Reductase.- 8. Other Reductases.- B. Aldehyde Oxidation.- I. Aldehyde Dehydrogenases.- II. Aldehyde Oxidase.- III. Xanthine Oxidase.- C. Summary.- References.- 52: Amine Oxidases.- Monoamine Oxidases.- 1. Isolation of MAO.- 2. Molecular Properties of MAO.- 3. Methods of Measurement of MAO Activities.- a) In Vitro Procedures.- b) Determination of MAO Activity in Materials Obtained from Living Persons.- 4. Substrate Specificity and Multiple Forms of MAO.- 5. Kinetic Studies.- 6. MAO Inhibitors.- a) List of Inhibitors.- b) Substrates as Inhibitors and Inhibitors as Substrates.- c) Propargylamine Derivatives.- d) ?-Alkylamines.- e) Cyclopropylamine Derivatives.- f) Hydrazine Derivatives.- g) Acylhydrazides.- h) Furazolidones.- i) Aromatic Amines and N-Heterocyclic Compounds.- j) Alcohols, Phenol, and Ethers.- k) Effect of the Substrate on Modality and Efficiency of MAO Inhibition.- 7. Mechanism of Interaction between MAO and its Substrates.- 8. Interaction between Inhibitors and MAO.- 9. On the Biological Function of MAO.- a) Occurrence of MAO in the Mammalian Organism.- b) Ontogenetic Changes in MAO Activity.- c) Effect of Hormones on MAO.- d) Protective Function of MAO.- e) Specific Functions of MAO.- References.- 53: Sulphate Conjugation Enzymes. With 3 Figures.- A. General Introduction.- B. The Activation of Sulphate.- I. The Sulphate-Activating System.- II. ATP-Sulphurylase.- III. APS-Kinase.- C. The Hydrolysis of Adenylyl Sulphates.- D. Sulphotransferases.- I. General Considerations.- II. Phenol Sulphotransferase.- III. Alcohol Sulphotransferase.- IV. Steroid Sulphotransferases.- 1. Introduction.- 2. Oestrone Sulphotransferase.- 3. Androstenolone Sulphotransferase.- 4. Aetiocholanolone Sulphotransferase.- 5. Testosterone Sulphotransferase.- 6. Desoxycorticosterone Sulphotransferase.- V. Arylamine Sulphotransferase.- E. The Synthesis of Sulphate Esters in Vivo.- References.- 54: Acetylating, Deacetylating and Amino Acid Conjugating Enzymes. With 3 Figures.- A. Acetylation and Deacetylation Enzymes.- 1. Acetylator Phenotyping.- 2. Assay Methods for N-Acetyltransferase in Mammalian Tissues.- 3. Properties of Mammalian Liver N-Acetyltransferase.- 4. Mechanism of Acetylation.- 5. Comparison of Liver N-Acetyltransferases from Rapid and Slow INH Acetylators.- 6. Comparison of Liver N-Acetyltransferases from Adult and Developing Rabbits.- 7. Evidence for Multiple N-Acetyltransferases.- 8. Deacetylation Enzymes.- 9. Comments on Evaluating the Relative Importance of Acetylating and Deacetylating Enzymes in Different Species.- B. Amino Acid Conjugating Enzymes.- 1. Properties of the Acyl Activating Enzyme System.- 2. Properties of the Acyltransferases.- C. Concluding Remarks.- References.- 55: Mercapturic Acid Conjugation. With 1 Figure.- I. Sources of the Cysteine Group that have been Proposed.- II. Glutathione as the Source of Cysteine.- III. Conversion of Glutathione Conjugates into Mercapturic Acids.- IV. Glutathione S-Transferases.- V. Glutathione S-Aryltransferase.- VI. Glutathione S-Epoxidetransferase.- VII. Glutathione S-Alkyltransferase.- VIII. Glutathione S-Aralkyltransferase.- IX. Glutathione S-Alkenetransferases.- X. Other Mercapturic Precursors.- 1. Arylamines.- 2. Urethane.- 3. Benzothiazole-2-Sulfonamide.- 4. Alkyl Methanesulfonates.- 5. 3,5-Di-tert-butyl-4-hydroxytoluene.- 6. Isovalthine.- 7. Bis-?-chloroethyl Sulfide.- 8. Nitrofurans.- Conclusion.- References.- 56: Methyltransferase Enzymes in the Metabolism of Physiologically Active Compounds and Drugs.- I. Catechol-O-Methyltransferase (COMT).- II. Phenol-O-Methyltransferase.- III. O-Methylation of Hydroxamic Acid.- IV. Hydroxyindole-O-Methyl Transferase (HIOMT).- V. Phenylethanolamine N-Methyl Transferase (PNMT).- VI. Histamine N-Methyltransferase.- VII. Non-Specific N-Methyltransferase.- VIII. Enzymatic Formation of Methanol from S-Adenosylmethionine.- References.- 57: Enzymes that Inactivate Vasoactive Peptides. With 2 Figures.- A. Introduction.- B. Inactivation of Kinins.- I. Kininases in Blood.- II. Carboxypeptidase N.- III. Kininase II.- IV. Converting Enzyme.- V. Kininases in Blood Cells.- VI. Kininases in Other Biological Fluids.- VII. Kininases in Tissues.- VIII. Inactivation of Kinins by Purified Proteases.- IX. Administration of Carboxypeptidase B.- X. Venoms.- XI. Microbial Kininases.- XII. Fate of Kinins in Vivo.- XIII. Inhibitors of Kininases.- XIV. Inhibition of Kininases in Vivo.- XV. Changes in Kininase Activity.- XVI. Enzymatic Conversion of Kinins.- C. Inactivation of Angiotensins.- I. Angiotensinases in Blood Plasma.- II. Angiotensinases in Blood Cells.- III. Angiotensinases in Other Biological Fluids.- IV. Angiotensinases in Tissues.- V. Use of Purified Proteases in the Determination of Angiotensin Structure.- VI. Fate of Angiotensins in Vivo.- VII. Inhibitors of Angiotensinases.- VIII. Changes in Angiotensinase Activity.- IX. Inactivation of Angiotensin in Vivo by Exogenous Enzymes.- D. Epilogue: The Importance of the Enzymes.- References.- 58: The Metabolism of Analogs of Endogenous Substrates: Wider Application of a Limited Concept. With 15 Figures.- A. Introduction.- B. Metabolism of Purine and Pyrimidine Analogs by Pathways of Normal Substrates.- I. General Background.- II. Metabolism of a Pyrimidine Analog: 5-Fluorouracil.- 1. The Pathways of Metabolism.- 2. General Interrelationship of Action and Metabolism of FU.- 3. Actions of Specific Metabolites of FU.- 4. Evaluation of Pharmacological Significance of Various Metabolic Routes.- III. Comparative Metabolism of 5-Halouracil Derivatives.- IV. Metabolism of a Purine Analog: 6-Thioguanine.- V. Metabolism of Other Purine and Pyrimidine Analogs.- VI. Clinical Applications of Knowledge on Metabolism of Purine and Pyrimidine Antimetabolites.- 1. Enhancement of Metabolism.- 2. Attempts to Increase Cell Penetrability of Active Metabolites.- 3. Selectively Increasing the Availability of Active Analog Metabolites.- 4. Spacing of Doses.- 5. Combination Therapy.- 6. Supplying Rescue Agents.- C. Metabolism of Other Analogs by Pathways for Normal Substrates.- D. The Metabolism of Substrate Analogs Along Routes Used by "Conventional" Drugs.- E. Summary.- References.- Author Index.