The involvement of gonads and gonadal steroids in the regulation of food intake, body weight and adiposity in the white Leghorn cock.

The effects of long-term injections of testosterone propionate (TP), diethylstilbestrol (DES) and TP+DES simultaneously to castrated and sham-operated White Leghorn cocks on feeding, weight gain, obesity, blood lipids and weight of various glands were studied. DES induced marked adiposity while TP reduced carcass fat content. Injections of TP+DES induced only moderate obesity. The responses of the castrated cocks to TP or DES were not always parallel to those of the sham-operated ones. In sham-operated cocks, TP induced permanent hypophagia and emaciation while in castrated cocks, although alleviating adiposity, it did not reduce the rate of weight gain and induced only a transient hypophagia. DES induced permanent hyperphagia and accelerated weight gain in sham-operated cocks while in those castrated, it induced only transient hyperphagia which later on changed into hypophagia. Although the latter cocks did not gain more weight than those castrated with no steroids supplementation, they were much more obese and had a fat content similar to that of the sham-operated ones treated with DES. The castration was found to alleviate the depressing effect of TP on adenohypophyseal and thyroidal weights. The results may suggest: (1) In the White Leghorn cocks, DES increases lipogenesis and food intake while TP results in the contrary. (2) Castration should not be considered as a lack of gonadal steroids only.