Response in Sinistrally Ovariotomized Leghorns to Daily Injections of Hebin. ∗

Abstract

We reported the precocious development of sexual characters in the juvenile Leghorn female following homeoplastic hypophyseal implants 1 as well as injections of hebin. 2 As a result of the daily injection of hebin, head furnishings responded by a phenomenal growth becoming large and masculine in character similar to that of treated males. Plumage and spurs exhibited no modifications, neither were changes observed in behavior. Postmortem revealed prominent ovaries which were larger and heavier than controls though revealed no signs of ovulation. Oviducts revealed pronounced hypertrophy comparable to that preceding ovulation. Thyroids were likewise conspicuously hypertrophied.

In an attempt to extend these observations 2 problems interested us particularly. The first was the source of the hormone causing masculinization of head furnishings in treated females. It was assumed that the medullary tissues of the rudimentary right gonad, as well as those of the left ovary, hypertrophied and elaborated male hormone. That this is a plausible explanation was revealed by our results following sinistral and dextral ovariotomy 3 in which the hypertrophied medullary tissues of either side were found to exert a masculinizing influence head on furnishings. Our results following sinistral ovariotomy logically would lead one to suppose that the masculinization of head furnishings following injections of hebin in the female is the result of hypertrophy of the rudimentary right gonad. However, since this organ exhibited relatively very little hypertrophy following these injections it was not considered as the major source of the hormone causing growth of head furnishings in these experiments. The second problem concerned a possible solution for the sporadic occurrence of spermatogenesis in the hypertrophied right gonad of early sinistrally ovariotomized Leghorns. Why does spermatogenesis occur in such a small percentage of cases in such individuals? Is it due to an insufficiency of gonad-stimulating hormone, during an early period when the primordial germ cells are still present, preventing active growth of the rudimentary right gonad and consequent incorporation of these cells? If so, then it might be expected that daily administration of hebin, immediately following early sinistral ovariotomy, would produce a greater percentage of fertile right testes in such individuals. Experiments were devised which might facilitate a solution of these problems.