THE PITUITARY BODY 



growth of the comb and testes of cockerels be used as a means 

 of assaying the gonadotropic hormone. 



3. The pigeon. — Riddle and Flemion (1928) produced a 

 marked stimulation of testicular growth in immature doves 

 by injecting repeatedly a glycerin extract of the anterior lobe 

 of the ox. The extract caused no clear-cut change in the size 

 of the ovaries of immature females. Homoplastic implants 

 brought about little, if any, change in the gonads of both 

 male and female birds. Riddle later (1931) concluded that 

 the injection of an extract of the mammalian pituitary into 

 the pigeon stimulated testicular growth far more than ovari- 

 an growth. According to Evans and Simpson (1934), the 

 testis of the immature pigeon is one of the most sensitive and 

 specific test-objects for the gonadotropic hormone(s) of the 

 pars glandularis. 



The anterior-pituitary hormone causing lactation ("pro- 

 lactin") brings about an involution of the testis of the pigeon 

 (Riddle and Bates, 1933). 



Smith and Engle (1927) observed no change in the ovaries 

 of immature mice which had received one implant of the 

 pigeon pituitary each day for 5 days. Likewise, Lipschiitz, 

 Kallas, and Wilckens (1929), although administering from 

 six to twelve pituitary glands of pigeons to immature mice, 

 produced uterine hypertrophy but no change in the ovaries 

 except in one mouse, in the ovaries of which there appeared 

 to be some growth of follicles. 



4. The duck. — All the experiments in ducks have been per- 

 formed in drakes. Schockaert (1931) injected various extracts 

 of the anterior lobe of the ox. In the immature drake this 

 treatment provoked a tremendous hypertrophy of the testis 

 (35-40 times the normal size) which might be accompanied 

 by precocious but complete spermatogenesis. The most 

 marked changes were produced in ducks 2.5-4 months old, 

 when the testis normally begins to grow rapidly. Benoit and 

 Aron (1934) were of the opinion that the testicular hypertro- 



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