title: Endothelial regulation of eNOS, PAI-1 and t-PA by testosterone and dihydrotestosterone in vitro and in vivo.
abstract: 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) Ser(1177)-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.
authors.affiliation: Department of Reproductive Medicine and Child Development, Molecular and Cellular Gynecological Endocrinology Laboratory (MCGEL), University of Pisa, Pisa, Italy.
authors.forename: L
authors.initials: L
authors.lastname: Goglia
authors.forename: V
authors.initials: V
authors.lastname: Tosi
authors.forename: A M
authors.initials: AM
authors.lastname: Sanchez
authors.forename: M I
authors.initials: MI
authors.lastname: Flamini
authors.forename: X-D
authors.initials: XD
authors.lastname: Fu
authors.forename: S
authors.initials: S
authors.lastname: Zullino
authors.forename: A R
authors.initials: AR
authors.lastname: Genazzani
authors.forename: T
authors.initials: T
authors.lastname: Simoncini
mesh_terms: D000818:Animals; D002478:Cells, Cultured; D013196:Dihydrotestosterone / Q000494:pharmacology*; D042783:Endothelial Cells / Q000187:drug effects* / Q000378:metabolism*; D005260:Female; D006801:Humans; D015151:Immunoblotting; D008297:Male; D009569:Nitric Oxide / Q000378:metabolism; D052250:Nitric Oxide Synthase Type III / Q000378:metabolism*; D017395:Plasminogen Activator Inhibitor 1 / Q000378:metabolism*; D051381:Rats; D017208:Rats, Wistar; D013739:Testosterone / Q000494:pharmacology*; D010959:Tissue Plasminogen Activator / Q000378:metabolism*
chemical_list: D017395:Plasminogen Activator Inhibitor 1; D013196:Dihydrotestosterone; D009569:Nitric Oxide; D013739:Testosterone; D052250:Nitric Oxide Synthase Type III; D010959:Tissue Plasminogen Activator