Richard E. Falvo

The relationship between men's endogenous levels of testosterone and their penile responses to erotic stimuli.

Abstract The endogenous levels of testosterone of six nonclinical, sexually functional men were compared to the magnitude and speed of development of their objectively measured penile erections to repeated presentations of an erotic film und to their self-reported sexual activity. Plasma testosterone concentrations were significantly correlated with two measures of the magnitude of film-elicited sexual arousal (i.e., both peak and mean erection) and with one measure of the speed of development of sexual arousal (i.e., the latency to 90% of full erection) but not with the other (i.e., the latency to 20% of full erection). There was also a significant inverse relationship between testosterone levels and their reported frequency of orgasm by any means. but the reported time from their last orgasm was not related to testosterone levels.

Nippostrongylus brasiliensis: Effects of testosterone on reproduction and establishment

Abstract Gonadectomy of the host reduced the establishment of Nippostrongylus brasiliensis in male mice, but elevated the recovery of worms from female hosts. Similarly, production of eggs by individual females of N. brasiliensis decreased and increased in gonadectomized male and female animals, respectively. Implantation of testosterone-filled capsules caused a dosage-dependent release of eggs by helminths in gonadectomized hosts of both sexes. Maximal production of eggs by nematodes was found when plasma testosterone in the host exceeded 20 ng/ml. Treatment of gonadectomized mice of both sexes with testosterone implants gave recoveries of worms that were similar to the number of helminths in intact male mice. Ligation of the bile duct of male mice that were implanted with testosterone reduced both establishment and reproduction of N. brasiliensis .