Compensatory Testicular Adjustments Following the Injection of Small Quantities of Androgen into Unilaterally Castrated White Leghorn Cockerels

THE growth and endocrine functions of the post-embryonic gonad in higher vertebrates are largely controlled by gonadotrophic hormones secreted by the anterior lobe of the pituitary gland. The relationship between the anterior pituitary and the gonads, however, is a complex one. Complete gonadectomy results in an enhancement of gonadotrophin production whereas gonadal steroid hormones when present in sufficient quantities may completely inhibit the secretion of gonadotrophins. These effects of variations in the level of circulating gonadal hormones have been known for many years (Moore, 1939), and Burrows (1949) has given an excellent review of the literature on the subject. The effects of intermediate levels of gonadal hormones on the pituitary-gonad axis, however, have not been extensively investigated. In addition, the data acquired from experiments with sub-total gonadectomy are not conclusive. It is the purpose of this paper to report some experiments on unilateral castration in the chick with the hope . . .