Growth and maintenance of the fowl's comb by administration of androsterone.

GREENWOOD et al. [1935] have discussed certain quantitative aspects of the capon comb response to androsterone. In view of the need for economy in both time and material a comparatively small degree of response is most suitable for assay work. Thus the criteria commonly used, a 20 % increase in area or an increase of 5 mm. in length+ height, take the capon comb only a fraction of the way towards the size of the normal cock's comb. Owing to lack of material and preoccupation with assay work, comparatively little effort has hitherto been made to produce and maintain full-sized combs in capons. Early in the work on the preparation of male hormone from testis, McGee et al. [1928] obtained comb growth in a Leghorn capon to a size (LxH) of 48 cm.2 in 5 weeks, about half the area (thus calculated) for a really good Brown Leghorn cock comb. Schoeller and Gehrke [1931] obtained an increase to 40 3 cm.2 in 6 weeks with urine concentrates. Ruzicka et al. [1934] obtained a surface area of 20 cm.2 (from 6-5 cm.2) in 20 days during early work with their "synthetic" androsterone and Ruzicka and Tschopp [1935] record an increase from 4 to 27 cm.2 in 16 days. The record comb of the literature, however, appears to have been produced by Freud et al. [1932]. As a result of nearly 4 months' injection of male hormone concentrate from bull testis, ultimately in a dose corresponding to 6 kg. of testis daily, they obtained a comb of 83 cm.2 (planimeter reading), which may be considered as being full size. This problem is of importance because there is some reason to suppose that androsterone may not represent the full endocrine activity of the mammalian testis, and an examination of the requirements for the complete replacement of testicular activity in birds should be instructive. We have also taken the opportunity of recording some observations on the effect of androsterone on the atrophic vas deferens.