PENILE GROWTH: TOPICAL VERSUS SYSTEMIC TESTOSTERONE THERAPY IN RATS

Publisher Website
Google Scholar
Abstract
Twenty-two day old weanling and 3-mo. old adult Sprague-Dawley rats were divided into 4 groups: normal, hypophysectomized, and orchidectomized weanlings and normal adults. Within each of the groups, rats were randomly assigned to 1 out of 8 treatment sub-groups. Body weight and tail length (as a measure of bone growth) were recorded serially during treatment. Topical treatment comprised 5% testosterone cream massaged on the penis 2, 5 or 10 times/wk. Appropriate applications of carrier cream base alone brought each animal up to 10 applications/wk. thus removing manipulation as a variable. I.m. testosterone was given in doses which corresponded to 20 and 200 mg/kg in weanlings and 3 and 30 mg/kg in adults. After the 30 day treatment period whole body radiographs for comparison of bone age were taken before death. In normal weanling rats, neither topical nor systemic treatment elicited penile growth that would produce a larger than normal adult penis. Neither therapy could change an adult rat''s penile size. Penile growth in hypophysectomized weanling rats, however, could be markedly increased with either therapy. In comparison to body weight these were truly large penises, but they fell short of being of normal adult size. In orchidectomized weanlings, penile size returned to normal with the high dose of testosterone. In 3 orchidectomized adult rats, serum testosterone rose from 1.1 .+-. 0.3 (S.E.M.) [standard error of the mean] to 123.6 .+-. 32.7 ng/ml per h after a single topical application of testosterone cream to the penis and maintained this level for 24 h. Topical testosterone therapy was not superior in producing penile growth, nor were there epiphyseal effects or growth considerations which would lead to favoring topical over moderate dose systemic therapy.

This publication has 0 references indexed in Scilit: