l-Arginine and tetrahydrobiopterin,but not sodium nitrite partially restored erectile dysfunction in aged rats

This paper gives an overview of our own studies and the literature on the biosynthesis and metabolism of estrogens in elderly men, the estrogen action in the male, and the clinical usefulness of estrogen therapy, including the phytoestrogens. Finally, the paper includes a short review of our knowledge of xenoestrogens and men's sexual health. A strong estrogen-deficient status is seen in male patients with mutations of the estrogen receptors or in cases of deviations of the aromatase gene. On the other hand, there are no clear age-dependent changes in estrogen secretion. But, in men with disorders of glucose metabolism and also of increased body mass index, the serum estrogen concentrations are significantly elevated. There are also strong positive correlations between serum estrogen levels and bone density, including prevalence of fractures and mood in men. New fields of interest are natural fatty esters of endogenous estrogens, e.g. lipoprotein-associated estrogens, and the role and clinical significance of tissue-specific, local estrogen biosynthesis (e.g. different promoters of the aromatase gene). Exogenous estrogen treatment is focused today on patients with normal testosterone and low levels of circulating estrogens documented on several occasions and with clinical symptoms of hormone deficiency; male-to-female transsexuals; and selected patients with prostate cancer. Some clinical studies show the benefits of estrogen treatment on some cardiovascular parameters and for treating selected signs of mental stress. An indirect estrogen replacement can occur if dehydroepiandrosterone is given orally to men. The clinical usefulness of dissociated estrogens, including non-feminizing estrogens and selective estrogen receptor modulators, is still an open question. The beneficial action of phytoestrogens in lowering the clinical symptoms of benign prostatic hyperplasia is well documented. Finally, the question about the definitive influence of so-called endocrine disruptors (xenoestrogens) on sexual functions in men is also discussed.