The use of antji~gonadotropic serum produced by immunization 
techniques will cause. inhibition of spermatogenesis and subsequent 
testis degeneration in mammals. A similar phenomenon may be 
exhibited in birds although there have been no encouraging 
reports (Tyler, 1961). 
6 Drugs. 
: There is a host of pharmocologically active substances 
that affect spermatogenesis of birds. Hudson and Pino (1952) 
found that Enheptin (2-amino, 5S-nitrothiazole) used at a 0.1 
per cent level in feed reduced testis size and spermatogenic 
_ activity (Table IV). They reported that 41.0 mg./kg. body weight 
caused complete suppression of sexual development in White 
Leghorn cockerels. When the Enheptin treatment was discontinued, 
Table Iv* 

Comb and Testes Changes in Control and Enheptin Fed 
White Leghorn Cockerels, (Average of 8 birds) 
Comb size Comb size Gain or Testes wt. 
start (cm) finish (om) loss (cm 
Control 50.6 80.7 + 30.1 14.72 
Enheptin 59.0 3069 ~ 28.1 0.38 
* Hudson an no, (195 
approximately 10 Weeketwmasresuired for recovery. These workers 
postulated that the action of the drug may be a pituitary tne 
volvement. Levis and Smyth (1957) reported that 0.1 per cent 
Enheptin fed to turkeys from 8 weeks of age, delayed spermatogenesis 
and age of sexual maturity. 
Zeller et al. (1958) found that lithospermum injection 
stopped egg production and reduced the size of comb, ovary and 
oviduct. Using lithospermum treatment in mammals, Drasher (1949) 
arid Noble et al. (1954) found that the gonadotropin titer of the 
pituitary was reduced. They suggested that there was an inhibition 
of L.H. activity. : 
Parizels (1960) in an extensive study with mammals 
found that salts of heavy metals caused testicular necrosis. Cad- 
mium salt (0.04 moles) resulted in increase of testis size in 
mammals a few hours after injection. This enlargement was fol- 
lowed by complete testicular necrosis. The animals took on the 
appearance of castrates. He concluded the effect was not through 
the pituitary. 
79 
