Modulation of serum testosterone and autonomic function through stimulation of the male human vomeronasal organ (VNO) with pregna-4,20-diene-3,6-dione.

In mammals, external chemosensory signals from conspecifics of the opposite sex acting on vomeronasal organ receptors can modulate the release of gonadotropins. There is developmental, anatomical and functional evidence showing that the human vomeronasal organ (VNO) has the characteristics of a chemosensory organ. We have been using naturally occurring human pheromones to serve as models for designing novel synthetic compounds that we call vomeropherins. In previous publications we reported that vomeropherin pregna-4,20-diene-3,6-dione (PDD) delivered to the VNO of normal female and male human volunteers significantly affected male subjects only, decreasing respiration and cardiac frequency, augmenting alpha brain waves, and significantly decreasing serum luteinizing hormone (LH) and follicle stimulating hormone (FSH). Results of the present work confirm that PDD produces a local dose-dependent effect in the male human VNO. This is followed by a mild parasympathomimetic effect characterized by 10% increase of vagal tone, together with decreased frequency of electrodermal activity events. Furthermore, PDD locally delivered to the male human VNO significantly decreases serum LH and testosterone (p < 0.01). The present results contribute additional evidence supporting the functionality of the human VNO and its repercussions in autonomic and psychophysiological functions, as well as in neuroendocrine secretions.