Effects of testosterone on vascular tone
Testosterone: Biochemistry, Therapeutic Uses and Physiological Effects, NOVA Publications , ss.159-183, 2012
- Yayın Türü: Kitapta Bölüm / Araştırma Kitabı
- Basım Tarihi: 2012
- Yayınevi: NOVA Publications
- Sayfa Sayıları: ss.159-183
- Sağlık Bilimleri Üniversitesi Adresli: Evet
Özet
Testosterone has classically been considered to exert an unfavourable effect upon the cardiovascular system. However, numerous recent clinical and epidemiological studies have reported a controversial relationship between testosterone and lipid profiles, inflammatory responses, hypertension, and altered vascular smooth muscle reactivity with regard to cardiovascular disease. Previous animal studies have demonstrated that testosterone exhibits a vasodilatory action in vasculature of experimental animals and more recently in isolated human pulmonary artery. Accordingly, we have recently shown that testosterone relaxes isolated human spermatic vein and corpus cavernosum as well as isolated human mesenteric, internal mammary and radial arteries. Because these effects occur in seconds to minutes, we and others have suggested that this action is likely to be mediated via the interactions with receptors on the membrane (nongenomic effect) rather than by interaction with the nucleus (genomic effect). Furthermore, several studies have shown the presence of the androgen receptor on the membrane of vascular smooth muscle cells, suggesting that the proposed mechanism is likely. While this effect frequently has been observed in large arteries at micromolar concentrations, more recent studies have reported vasorelaxation of smaller resistance arteries at nanomolar (physiological) concentrations. The data from in vitro studies suggest that vasodilatory effect of testosterone is mediated via inhibition of Ca2+ influx into the smooth muscle cell. On the basis of the data reported to date, the exact mechanisms underlying this physiological effect of testosterone remain unclear and might involve activation of K+ channels and antagonism of Ca2+ channels, are likely to be of nongenomic signaling, and might not require the endothelium. Taken as a whole, a considerable body of evidence suggests that testosterone causes relaxation of the vasculature and it could have useful therapeutic roles in hypertension, angina, erectile dysfunction, prostatic ischemia, or other vascular dysfunctions. © 2012 Nova Science Publishers, Inc. All rights reserved.