THE GONADOTROPIC HORMONES 



tary function, (a) Hormones of the oestrin groupr'^^^'' — The 

 effects of hormones of the oestrin group on the secretory per- 

 formance of the pituitary, aside from their pharmacological 

 interest, are important because they furnish a basis for inter- 

 preting the interplay of ovarian and pituitary (gonadotropic) 

 hormones. This is true although only one member of the 

 group (oestradiol) probably is a normal secretion of the ovary. 

 Particularly in the preceding sections, other aspects of this 

 problem have been mentioned. The experimental data about 

 to be taken up here extend our knowledge by other technics. 

 The early experiments of Meyer, Leonard, Hisaw, and Mar- 

 tin (1930, 1932) demonstrated the diminished gonadotropic 

 potency of the pituitary of rats which had received injections 

 of oestrin for 4-10 weeks. The publication of their work was 

 followed by numerous reports of related phenomena, which, 

 as far as recent articles are concerned, now require discussion. 

 Berkowitz (1937) repeatedly added tablets of "Progynon" 

 (oestrone.^) for a long period to the tank water in which he 

 kept immature male guppies {Lebistes reticulatus). In size, 

 shape, and color the fish ultimately resembled females. No 

 spermatogenesis appeared. The author believed that the 

 treatment accelerated growth. He was unable to demonstrate 

 that the tablets had any effect on adult male fish. The injec- 

 tion of large doses of oestradiol benzoate into the cock causes 

 regression of the comb and spurs (Zondek, 1936). Bates, 

 Riddle, and Lahr (1937) concluded that testicular atrophy 

 occurs if oestrone be injected into adult male ring doves (40 

 rat-units per day for 10 days). All these effects, like similar 

 effects in mammals, probably depend upon an interference 

 with the secretion of gonadotropic hormones by the pituitary 

 body. Oestrone is said not to affect the egg-laying perform- 

 ance of the fowl (Unik and Liptschina, 1934). 



^' Particularly oestradiol, oestrone, and oestriol, and their esters. 



3° According to Miiller (1937), the dose of oestradiol necessary to produce the 

 vaginal signs of oestrus in the thymectomized or spayed rat is much higher as a 

 result of hypophysectomy. These results are contrary to those of Smith (1932J, 

 who used oestrin. 



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