Is there an inhibitory role of cortisol in the mechanism of male sexual arousal and penile erection?

Background. It has been speculated for more than 2 decades whether there is a significance of adrenal corticosteroids, such as cortisol, in the process of normal male sexual function, especially in the control of sexual arousal and the penile erectile tissue. However, only few in vivo studies have been carried out up until now on the effects of cortisol on human male sexual performance and penile erection. In order to evaluate further the role of cortisol in male sexual activity, the present study was conducted to detect serum levels of cortisol in the systemic and cavernous blood taken during different penile conditions from healthy males. Material and Methods. The effects of cortisol derivative prednisolone, catecholamine norepinephrine (NE) and the peptide endothelin-1 (ET-1) on isolated human corpus cavernosum (HCC) were investigated using the organ bath technique. Fifty-four healthy adult male subjects were exposed to erotic stimuli in order to elicit penile tumescence and rigidity. Whole blood was simultaneously aspirated from the corpus cavernosum and the cubital vein during different penile conditions. Serum levels of cortisol (μg/dl) were determined by means of a radioimmunoassay (ELISA). Results. In the healthy volunteers, cortisol serum levels significantly decreased in the systemic circulation and the cavernous blood with increasing sexual arousal, when the flaccid penis became rigid. During detumescence, the mean cortisol level remained unaltered in the systemic circulation, whereas in the cavernous compartment, it was found to decrease further. Under all penile conditions, no significant differences were registered between cortisol levels in the systemic circulation and in the cavernous blood. Cumulative addition of NE and ET-1 (0.001–10 μM) induced contraction of isolated HCC strips, whereas the contractile response to prednisolone was negligible. Conclusion. Our results strongly suggest an inhibitory role for cortisol in the mechanism of male sexual response and behaviour. These properties are mediated rather via an effect on central structures than on the penile erectile tissue. Future studies to include patients suffering from erectile dysfunction may reveal whether or not there are differences in the cortisol serum profiles of healthy subjects and patients under different stages of sexual arousal.