A possible role of protein synthetic processes in the testosterone-activation of penile reflexes in rats was examined in these experiments. In Experiment 1, long-term castrated male rats were injected with 250 μg testosterone propionate (TP) and tested for penile reflexes 24 hr later. Fifteen minutes prior to TP these males received a systemic injection of the protein synthesis inhibitor anisomycin (ANI) or the saline vehicle. ANI had no disruptive effect on the activation of penile reflexes by TP; in fact, ANI facilitated erection frequency. In Experiments 2 and 3, a series of three ANI or saline injections were given at 2 hr intervals beginning with the injection of 250 μg TP, with no significant effect on any reflex parameters tested 12 or 24 hr after TP. In Experiment 4, the penile reflexes of male rats were stimulated by implanting a Silastic capsule containing testosterone subcutaneously for 2 weeks. A series of ANI or saline injections were spaced 3 hr apart, with penile reflexes tested 6 and 12 hr after the first injection. There were no significant differences between ANI and saline-treated males at 6 hr, whereas at 12 hr ANI-treated males had significantly shorter reflex latencies and significantly more penile flips than did males injected with saline. In a final experiment (Experiment 5), the Silastic capsules were removed from the males in the previous experiment. Three injections of ANI or saline were given at 4 hr intervals beginning with the removal of the Silastic capsule. When tested 24 hr after Silastic removal, no differences in penile reflex parameters between males treated with ANI or saline were detected. Although steroids are classically thought to act through the stimulation of protein synthesis, our results suggest that the testosterone-activation of penile reflexes does not involve genomic events.
Bibliographical noteFunding Information:
This research was supported by NIH Grants HD-08933 (B.D.S.) and HD-21478 (R.L.M.). We would like to thank Ms. Linda Miller for her technical assistance with these experiments.
- Penile reflexes
- Protein synthesis inhibition