Reversibility in Testicular Toxicity Assessment

REVERSIBILITY IN MALE REPRODUCTIVE RISK ASSESSMENT: THE GERMINAL CELLS (ROBERT H. FOOTE AND WILLIAM E. BERNDTSON). PREPUBERTAL TESTIS. GERMINAL CELLS OF THE SEXUALLY MATURE MALE. Dynamic Process of Spermatogenesis. General Classes of Germ Cells. Kinetics of Spermatogenesis. Intercellular Bridges between Cells Derived from Single Stem Cells. FACTORS AFFECTING GERMINAL CELLS. General Genetic and Environmental Agents. Nutrition. GERMINAL CELL SENSITIVITY TO NOXIOUS AGENTS. General Factors Affecting Sensitivity. CHOICE OF AGENTS TO SERVE AS EXAMPLES. Background. Dibromochloropropane (DBCP). Ethylene Dibromide (EDB). Triethylenemelamine (TEM). Cadium. Summary of Mechanisms of Action. ENDPOINTS AND TECHNIQUES. General. Choice of Animal Models. Rat and Rabbit as Test Species: Endpoints. EXPERIMENTAL DESIGN. FUTURE NEEDS. THE SERTOLI CELL (PAUL M. D. FOSTER). THE SERTOLI CELL AND ITS PIVOTAL ROLE IN SPERMATOGENESIS. Structure and Compartmentation. Physiologic Function. Stage Specific Influences. NORMAL CONTROL OF SERTOLI CELL FUNCTION. Endocrine. Paracrine. Autocrine. THE SERTOLI CELL AS A TARGET FOR TOXICANT ACTION. Introduction. Phthalate Esters. m-Dinitrobenzene (and Other Nitroaromatics). 2,5-Hexanedione (HD). Others. DISCUSSION. THE LEYDIG CELL (LARRY L. EWING). ROLE OF THE LEYDIG CELL IN MAMMALIAN REPRODUCTION. Life History. Structure and Function. Regulation of the Leydig Cell. BIOMARKERS OF LEYDIG CELL IMPAIRMENT AND DEATH. Peripheral Effects. Intratesticular Effects. COMPOUNDS THAT IMPAIR AND/OR KILL LEYDIG CELLS. Ethanol. Cannabinoids. Drugs and Medicinals. Metals. 1, 2-Dibromo-3-Chloropropane (DBCP). 2,3,7,8-Tetrachlorodibenzo-p-Dioxin (TCDD). Estrogens. COMPOUNDS THAT CAUSE LEYDIG CELL HYPERPLASIA/NEOPLASIA. EXPERIMENTAL MODELS. Testosterone-Estradiol Silastic Implants. Ethylene Dimethanesulfonate (EDS): A Leydig Cell Cytotoxicant. SUMMARY. REVERSIBILITY OF DAMAGE TO TESTICULAR VASCULATURE RESULTING FROM EXPOSURE TO TOXIC AGENTS (CURTIS CHUBB). THE CIRCULATORY SYSTEM. General Description. The Uniqueness of the Endothelium. Endothelium Surface Charges. TESTICULAR VASCULATURE. General Description. Unique Aspects of Testicular Vasculature. METHODS OF STUDY. In Vivo Study of Testicular Microvasculature. In Vivo Study of Extratesticular Microvasculature. Animal Models for Blood Vessel Toxicity Studies. In Vitro Methods for the Study of Testicular and Extratesticular Microvasculature. TOXIC AGENTS AFFECTING TESTICULAR VASCULATURE. Lead. Cobalt. Cadmium. STUDIES OF TESTICULAR VASCULATURE REGENERATION. Regeneration Following Acute Cadmium Exposure. Regeneration Following Focal Destruction. Regeneration Following Surgically-Induced Ischemia. PARTICIPATION OF ENDOTHELIUM IN GENERAL TOXICITY OF TESTES. CRITIQUE OF PREVIOUS INVESTIGATIONS. CONCLUSIONS.