MAMMALIAN TESTIS 



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Fig. 5.10. Diagrammatic drawings of stages I to XIV of the f\cle ul ilie seminiferous 

 epithelium. Drawings made from PAS-hematoxylin stained preparations. Numbers 1 to 

 19 refer to spermatids at different steps of spermiogenesis. A, type A spermatogonia; B, 

 type B spermatogonia; Bm, mitosis of spermatogonia; R, resting spermatocytes; L, lep- 

 totene stage; Z, zygotene stage; P, pachytene, Di, diplotene and diakinesis; SI, primary 

 spermatocytes; Sim, primary spermatocyte metaphase; SI I, secondary spermatocytes; 

 Slim, secondary spermatocyte metaphase; S, Sertoh element; Rh, residual body. (From 

 R. Daoust and Y. Clermont, Am. J. Anat., 96, 255. 1955.) 



not arise from supporting cells (Clermont 

 and Perey, 1957). 



It was known that, after hypophysec- 

 tomy, spermatids disappear but sper- 

 matogonia, Sertoli cells, and primary sper- 

 matocytes remain for long periods and 

 spermatogonial mitosis continues. Clermont 

 and ]\Iorgentaler (1955) noted spermatids 

 being phagocytosed by the Sertoli cells 

 within 3 days after hypophysectomy. Young 

 spermatids at stages 1 through 7 are present, 

 but at 10 days after hypophysectomy, no 

 developing spermatid has reached stage 9. 

 A few pachytene spermatocytes are de- 

 generating, but primary and secondary 

 spermatocytes are present during the first 

 week after the operation. By the tenth day, 

 the Sertoli cells shrink but do not disin- 

 tegrate. Spermatogonial types A and B re- 

 main intact. Maximal regression after hy- 

 pophysectomy is reached within 29 days. 



The basement membrane is thick and there 

 are two rows of type A, intermediate, and 

 type B spermatogonia, a few primary and 

 secondary spermatocytes, spermatids at 

 stages 1 through 7, and Sertoli cells. Type 

 B cells form spermatocytes, but the sper- 

 matocytes degenerate before and during 

 meiosis, and only 4 per cent of them survive 

 to produce spermatids. The spermatids de- 

 velop to stage 7 and then disintegrate. 

 Therefore, spermatogenesis up to stage 7 of 

 spermiogenesis can occur in the absence 

 of the pituitary gland but at a greatly re- 

 duced rate. As was surmised from early ob- 

 servations on the maintenance of sperma- 

 togenesis by androgen, the premeiotic phase 

 of spermatogenesis apparently can take 

 place without gonadotrophins ; meiosis suf- 

 fers severely from gonadotrophic depriva- 

 tion; and the postmeiotic phase is controlled 

 by androgen. The observation that testos- 



