The effect of gonadal and thyroidal hormones on the regulation of food intake and adiposity, and on various endocrine glands, in the red-winged blackbird (Agelaius phoeniceus)

The effects of testosterone propionate (TP), clomiphene citrate (CC), thyroxine (T₄, and propilthiouracil (PTU) on food and water intake, adiposity, and various endocrine glands of male red-winged blackbird were studied. TP induced hyperphagia with obesity, increased prolactin cell population in the pituitary, and supressed the gonadotropic activity. CC had the opposite effects to TP. T₄ induced hyperphagia without obesity, increased somatotrops population in the adenohypophysis, but suppressed thyrotropic and gonadotropic activities. PTU reduced food intake without affecting adiposity and enhanced throtropic activity while supressed the gonadotropic one. All treatments induced enlargement of the adrenal cortex. The relationships among the various effects are discussed.