GONADS AND THE PITUITARY BODY 



lowing effects." The head furnishings grew rapidly so that 

 the pullets resembled males. No ovulation was produced, 

 but the oviducts became enlarged. As a result, especially of 

 the injection of the extract, the ovary, the rudimentary 

 right gonad, and the Wolffian ducts underwent hypertrophy. 

 All these effects were prevented by the removal of the ovary 

 (left gonad). Domm concluded that a stimulation of the me- 

 dulla of the ovary caused a liberation of "testicular" hormone 

 so that the head furnishings grew to resemble those of the 

 male; the growth of the oviduct he attributed to a liberation 

 of ovarian hormone from the cortex of the ovary. 



1. The male fowl. — Domm (1931-33) caused a marked stim- 

 ulation of the testis of the fowl (3-12 weeks old) by adminis- 

 tering a homo-implant once daily for 19-28 days. The head 

 furnishings became swollen and red, and grew markedly. 

 Older cockerels were observed to crow and tread. Not only 

 did the implants bring about a testicular hypertrophy, but 

 spermatogenesis was also precociously accelerated so that 

 mature spermatozoa were formed. Domm had the impres- 

 sion (as in his experiments with pullets) that implants taken 

 from capons were the most effective, whereas those from 

 cocks and hens — particularly the latter — were less effec- 

 tive. All the changes were prevented by gonadectomy. Like- 

 wise, all the foregoing effects, except the production of ma- 

 ture spermatozoa, were produced by the repeated injection 

 of a gonadotropic extract of the sheep pituitary (Domm and 

 van Dyke, 1932). Dingemanse and Kober (1933), who em- 

 ployed an extract of the anterior lobe of the ox, produced 

 comb growth but no testicular change in cockerels. On the 

 other hand, Vacek (1934) concluded that the injection of an 

 extract of the pars glandularis of the pig actually caused a 

 testicular regression with failure in the development of the 

 head furnishings. Schockaert (1932) proposed that the 



" Mitchell (1932) was unable to cause changes in the ovary or oviduct of young 

 pullets receiving implants of the pars glandularis of the chick. 



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