Maintenance Of Sexual Behavior Research Articles

Maintenance of sexual behavior in castrate male SW mice using the anti-androgen, cyproterone acetate

The present study was designed to test the hypothesis that cyproterone acetate (C) might selectively block the actions of dihydrotestosterone (D) and via this action, function as an anti-androgen in male sexual behavior. Sexually experienced male SW mice, a strain previously shown to respond to D following castration, were divided randomly into six groups. Beginning on the day after castration, animals received SC injections for 21 days of either testosterone (T), (D), (C), (T+C), (D+C) or vehicle (V). C was found to significantly reduce seminal vesicle and body weights in all androgen treated groups. There was no evidence to support the contention that C selectively blocks the action of D. To the contrary, in sex tests C maintained palpations, thrust mounts, mounts with intromissions and mounts with ejaculations. Indeed, only animals receiving C alone or in combination with T or D exhibited ejaculations throughout the testing. These results suggest that in the SW mouse, C can work like an androgen in the maintenance of male sexual behavior.

Aromatization of Androstenedione by the Anterior Hypothalamus of Adult Male and Female Rats

Homogenates of fresh tissue from adult male and female rats were incubated with appropriate co-factors and androstenedione-3H for one hour at 37° C. Extraction and identification of reaction products demonstrated the aromatization of androstenedione to estrone by anterior hypothalamus but not by posterior hypothalamus, anterior pituitary gland or frontal cortex. This finding confirms and expands the previous preliminary report of aromatization by human fetal hypothalamus to include adults of both sexes in a second species, the rat. Further localization of this reaction is consistent with concepts derived from experimental evidence which indicate central aromatization of androgens to be involved in sexual differentiation of the brain, initiation and maintenance of sexual behavior, control of gonadotropin secretion and “peripheral conversion” of circulating androgens to estrogens. (Endocrinology 90: 295, 1972)

Testosterone, androstenedione and dihydrotestosterone: Effects on mating behavior of male rats

The relative effectiveness of testosterone, androstenedione, and dihydrotestosterone in maintaining mating behavior following castration of male rats was studied. In Experiment 1 testosterone, but not dihydrotestosterone, was found to maintain mating. In Experiment 2 testosterone and androstenedione were found to be equally effective in maintaining mating. Dihydrotestosterone failed to maintain mating and was no more effective than no treatment at all. Testosterone, androstenedione, and dihydrotestosterone significantly enhanced seminal vesicle and penis weight. In Experiment 3 castrated male rats were administered radiolabeled testosterone, androstenedione, or dihydrotestosterone. Radioactivity was found in hypothalamic and seminal vesicle samples indicating that these steroids can be accumulated by brain as well as peripheral androgen-sensitive tissues. It was concluded that the peripherally active steroid dihydrotestosterone probably plays no role in the maintenance of sexual behavior.