1068 



SUBMAMMALIAN VERTEBRATES 



in that the ovarian cortex was thinner, and 

 the medullary cords were larger and more 

 numerous, than in the controls. No acces- 

 sory structures were affected. 



Juvenile diamond-back terrapins, Mala- 

 clemmys centrata, were also injected with 

 testosterone propionate (Risley, 1941b ». In 

 the males there resulted cavitation of the 

 medullary cords and slight growth of Miil- 

 lerian ducts. In the females ovarian and 

 follicular size were less than normal, and 

 Miillerian ducts grew conspicuously. Wolf- 

 fian ducts and ureters hypertrophied in both 

 sexes. Estradiol dipropionate injections 

 caused reduction of testis size but growth of 

 its cortical remnant and of Miillerian ducts, 

 Wolffian ducts, and ureters in both sexes. 



Classic studies on sex reversal in lizard 

 embryos of an unidentified species have 

 been made by Dantchakoff (1938). Fertile 

 eggs were removed surgically from the 

 mother, 8 to 12 being obtained at each 

 operation. An injection of 0.05 to 0.15 mg. 

 folliculin (an estrogen) in sesame oil was 

 made into the egg under the blastoderm. 

 Treated eggs and their controls were opened 

 and examined 2 weeks after injection, ap- 

 proximately 2 weeks before hatching, 1 

 week before hatching, or 3 to 5 days after 

 hatching. Estrogen treatment converted the 

 testes to "hypo-ovaries." The medulla was 

 inhibited, and a true cortex was developed, 

 although it was thinner than in a normal 

 female. In treated females the ovarian cor- 

 tex and medulla were hypertrophied. In 

 experimental embryos of both sexes large 

 Miillerian ducts were present, although the 

 ducts were often incomplete in the males. 

 (Miillerian ducts were always absent at 

 hatching in control males.) Estrogen did not 

 appear to affect the mesonephric ducts. The 

 cloacal epithelium of treated males and fe- 

 males was transformed, as Dantchakoff 

 points out, very much in the manner de- 

 scribed by Allen and Doisy (1923) for the 

 vaginal epithelium of rodents in estrus. The 

 epithelium had increased from 2 or 3 to 25 

 or 30 cell layers in thickness. The ureters 

 were unaffected, but the cloacal extremities 

 of the Wolffian ducts and the bladder-like 

 diverticulum of the cloaca showed epithelial 

 hypertrophy and metaplasia. Dantchakoff 

 concluded that folliculin helps to control the 



normal development of the female repro- 

 ductive system in the lizard, particularly in 

 regulating Miillerian duct growth and in 

 the "feminine orientation" of the indifferent 

 gonad. From this she reasoned that follicu- 

 lin is not present in the normal male em- 

 bryo. 



Implantation of testosterone propionate 

 pellets into gonadectomized and intact, im- 

 mature and adult Anolis of both sexes 

 (Noble and Grcenberg, 1940, 1941) resulted 

 in oviduct hypertrophy in all females as 

 compared to untreated controls. 



Pellets of testosterone propionate or es- 

 tradiol dipropionate were implanted sub- 

 cutaneously in gonadectomized and intact, 

 male and female, immature and adult Anolis 

 (Noble and Greenberg, 1940, 1941). In the 

 females both hormones caused conspicuous 

 oviduct hypertrophy and extreme keratini- 

 zation of urodeal cloacal epithelium. The 

 androgen also produced hypertrophy of the 

 ovaries. Wolffian ducts, and "sexual seg- 

 ments" of the kidneys. Both hormones 

 caused a similar keratinization of the cloaca 

 in males, whereas androgen evoked hyper- 

 trophy of the Wolffian duct and sexual seg- 

 ment and maintained in normal condition 

 the epididymis and vas deferens of adult 

 castrate males. Forbes (1941) implanted 

 either testosterone or estrone in adult male 

 Sceloporus. Treatment was followed by 

 some reduction in testicular volume, ac- 

 celeration of spermatogenesis, hypertrophy, 

 and mucosal hyperplasia of persisting seg- 

 ments of JNIiillerian duct, apparent stimula- 

 tion of the femoral glands, and hypertrophy 

 of the epididymides and vasa deferentia. 

 Absorption of estrone resulted in reduction 

 of testicular volume, and spermatogenesis 

 almost ceased. Seminiferous and cpididymal 

 tubules and femoral and cloacal glands be- 

 came atrophic, as did the cells of the sexual 

 segments. On the other hand, there was 

 great hypertrophy of the Miillerian duct 

 vestiges and stratification and cornification 

 of the urodeal and proctodeal mucosa. It is 

 believed that in mammals the administra- 

 tion of either sex hormone depresses the re- 

 lease of pituitary gonadotrophin, thus re- 

 moving endocrine support for the gonad, but 

 that testosterone also acts directly to stimu- 

 late both spermatogenesis and accessory sex 



