ALLAN J. STANLEY, LAURENCE G. GUMBRECK and JOHN E. ALLISON,     Departments of Physiology and Biophysics and of Anatomical Sciences, The University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma

RONALD B. EASLEY,     Duke University Hospital, Durham, North Carolina

Publisher Summary

This chapter presents an analysis of male pseudohermaphroditism in the rat with regard to anatomic, embryologic, genetic, and physiological considerations. The anomaly is transmitted genetically by female carriers to one-half of their male offspring. In addition, one-half of the female offspring of an affected sibship become carriers. Affected males exhibit, in general, a female phenotype characterized by the presence of a blindly ending vaginal recess and mammary line but lack both Müllerian and Wolffian duct systems. Embryologic studies show normal development of Wolffian and Müllerian duct systems up to day 17 in utero, at which time disintegration of these structures takes place. Hence, a male inductor system seems not to be involved, but rather a maintenance factor without which disintegration of the ductal system results. The lack of androgen sensitivity demonstrated in these animals appears to be a reasonable explanation in light of present information. Spermatogenesis does not progress beyond the primary spermatocyte stage in the testes of the pseudohermaphrodite. The interstitial cells show marked proliferation, an indication of gonadotropin stimulation.

I Introduction

In 1941, D’Amour and Funk in a paper entitled “Spontaneous Inter-sexuality in the Rat” described anatomically a condition closely resembling one that has appeared in our rat colony and has been successfully isolated and propagated as a substrain of our King2 × Holtzman hybrids. Eight individuals appeared in their colony over a period of two years, and, although attempts were made to find the parents of these animals, they could not be identified and the stock was subsequently lost. The only additional case of this type of intersex in the rat was reported by Matthews (1947) in a single specimen of the wild Norway rat. This animal possessed nipples, a perforate vagina, two flattened sterile testes and other rudimentary accessories.

The following trivial names and abbreviations have been used in the text and discussion: adrenosterone = androst-4-che-3,11,17-trione; androstenedione = androst-4-ene-3,17-dione; androsterone = 3α-hydroxy-5α-androstan-17-one; dehydroepiandrosterone = 3β-hydroxy-5-androsten-17β-01; deoxycorticosterone = 21-hydroxypregn-4-one-3,20-dione; estrone = 3-hydroxyestra-1,3,5(10)-trien-17-one; 17β-estradiol = estra-1, 3,5(10)-triene-3,17β-diol; estriol = estra-1,3,5(10)-triene-3,16α,17β-triol; etiocholanolone = 3α-hydroxy-5β-androstan-17-one; progesterone = pregn-4-ene-3,20-dione; 17-hydroxyprogesterone = 17-hydroxypregn-4-ene-3,20-dione; pregnenolone = 3β-hydroxy-5-pregnen-20-one; 17-hydroxypregnenolone = 3β,17-dihydroxy-5-pregnen-20-one; testosterone = 17β-hydroxyandrost-4-en-3-one; PMS = pregnant mare serum; HCG = human chorionic gonadotropin; FSH = follicle-stimulating hormone; LH, luteinizing hormone.

II Materials and Methods