Response in Unilateral and Bilateral Castrate Leghorns to Daily Injections of Hebin. ∗

Abstract

We previously reported the precocious development of sexual characters in cockerels following homeoplastic hypophyseal implants 1 and later a similar effect was reported following daily injections of hebin. 2 These experiments not only revealed a profound response on the part of head furnishings and behavior but primary and accessory sexual characters were affected as well. Following injections of hebin head furnishings soon became many times larger than controls and masculine in character. Cockerels crowed as early as 9 days of age and began treading at 13. On postmortem testes and ductus deferens deferens definite and frequently pronounced hypertrophy. Thyroids likewise were larger and heavier than controls. Histological examination of testes revealed significant modifications. The tubules of treated testes were, in all cases examined, distinctly larger and more advanced in development and in many cases revealed complete spermatogenesis.

In view of these interesting results on normal cockerels it was considered advisable to study the effects of similar experiments in unilateral and complete castrates. Accordingly a group of left unilateral castrates, a group of right unilateral castrates, and some capons were given daily subcutaneous injections of hebin. Ages at the time injections began were 28 and 35 days. Castrations in all cases having been done 2 to 3 days before the injections began. The duration of injections was 21 and 22 days. The dosages were 10 and 20 rat units in single daily injections. All individuals in the experiments were weighed and head furnishings measured at regular intervals. Treated birds were not adversely affected by the injections.

It was found that unilateral castrates responded much as did normals following daily injections of hebin. Pronounced growth of head furnishings was manifested just as early as in normals and was equally pronounced. The capon, however, revealed no such response. The head furnishings here remained small and pale throughout and revealed no growth. Behavior was likewise unmodified, remaining typically capon throughout.