Endothelial regulation of eNOS, PAI-1 and t-PA by testosterone and dihydrotestosterone in vitro and in vivo

• Published in: Molecular human reproduction 2010-10, Vol.16 (10), p.761-769
• Main Authors: Goglia, L., Tosi, V., Sanchez, A.M., Flamini, M.I., Fu, X.-D., Zullino, S., Genazzani, A.R., Simoncini, T.
• Format: Article
• Language: English
• Subjects: androgens; Animals; cardiovascular disease; Cells, Cultured; Dihydrotestosterone - pharmacology; endothelial cells; Endothelial Cells - drug effects; Endothelial Cells - metabolism; Female; fibrinolysis; Humans; Immunoblotting; Male; nitric oxide; Nitric Oxide - metabolism; Nitric Oxide Synthase Type III - metabolism; Plasminogen Activator Inhibitor 1 - metabolism; Rats; Rats, Wistar; Testosterone - pharmacology; Tissue Plasminogen Activator - metabolism
• ISSN: 1360-9947; 1460-2407
• DOI: 10.1093/molehr/gaq049

The aim of this study is the identification of direct endothelial regulation by the androgens testosterone (T) and dihydrotestosterone (DHT). We tested the effects of T and DHT on nitric oxide (NO) synthesis and on tissue plasminogen activator (t-PA) and plasminogen activator inhibitor-1 (PAI-1) expression in human endothelial cells and in ovariectomized (OVX) rats. The results showed that at physiological concentrations T and DHT increase endothelial synthesis of NO. This depends on a rapid recruitment of the extracellular-related kinase (ERK) 1/2 and of the phosphatidylinositol 3-OH kinase (PI3K)/Akt cascades, resulting in endothelial nitric oxide synthase (eNOS) Ser1177-phosphorylation. In addition, a later increase of eNOS expression is found. With supra-physiological amounts of T or DHT the induction of NO synthesis is lost. A concentration-related increase of t-PA expression starting from physiological concentrations of T or DHT is found, whereas PAI-1 is augmented only with higher doses. Although DHT exerts these actions through androgen receptors (AR), T acts in part through aromatase-dependent conversion to 17β-estradiol. Ovariectomy is associated with significant changes in eNOS, t-PA and PAI-1 expression in the aorta of Wistar rats and T and DHT result in modifications on eNOS, PAI-1 and t-PA that are in line with the in vitro experiments. In conclusion, T and DHT act on endothelial cells through AR or via conversion to estradiol. Physiological, but not higher amounts are associated with enhanced NO synthesis and an increased t-PA/PAI-1 ratio. These findings are useful to understand the impact of androgens in ageing individuals.