Is there a role of hypoxemia in penile fibrosis: a viewpoint presented to the Society for the Study of Impotence.

During erection, oxygen tension changes in the corpus cavernosum penis from 25-40 mm Hg in the flaccid state to 90-100 mm Hg in the erect state. The relationship between corpus cavernosum trabecular structure and erectile function is dependent on a critical balance of smooth muscle to connective tissue for successful veno-occlusion. In this article, the potential role for transforming growth factor beta(1) (TGF-beta(1)) and prostaglandin E (PGE) in maintaining a functional smooth muscle/connective tissue balance are discussed as well as the importance of oxygen tension in the synthesis of these factors. Correlations between animal models of disease as well as clinical reports are presented in support of a role for hypoxemia in penile fibrosis. A case is presented for a biological basis of nocturnal penile tumescence in the preservation of potency and an overall hypothesis for the molecular pathology of erectile dysfunction is proposed.