| Endothelin- 1 is produced by Sertoh Cells in testis and stimulates testosterone secretion by Leydtg cells as a paracrine factor The aim of the present study is to find the signal cascade of ET-1 on Leydig cells and effects of ET-1 on testosterone synthesis pathway Methods Part 1 Purified rat Leydig cells were exposure to a senes of concentration of El-i (0.01-100ng/ml) and hCG (0-100ng/ml), and then hCG (lngIml), inhibitors of PKC and PKA (OF 109203X iuM and H89 lOnM respectively), Ca2+ channel antagomst (nifedipine 100uM) and Ca2+ (3mM) were added to the El-i treated Leydig cells After 24hs treatment, the medium was collected to determine testosterone concentration Part 2 Total RNA of El-i treated Leydig cells was extracted by lnzoi The quantity of StAR and P4SOscc mRNA were measured by Nothern Blotting and quantitative RT-PCT Results 1) El-i increased testosterone secretion up to 3 fold by a dose-related fashion at the concentration of 01-100ng/ml, 2) El-i had a clear-cut additive effects with hCG, 3) The secretagogue action of ET-1 was blocked by OF 1 09203X, but not by H89 and nifedipine, 4) the concentration of calcium in the culture medium did not modify I response to ET-1 5) The mRNA expression of StAR and P45Oscc increased by 55 6% and Si 5% respectively after exposure to ET-1 Conclusions 1) El-i concentration-dependently increased testosterone secretion and had additive effects on hCG stimulated I production, 2) The main signal cascade of El-i on Leydig cells was PKC activation, which is totally different from that of hCG, and voltage-operated Ca channels were not involved 2) El-i increased mRNA expression of StAR and P4SOscc... |
PDF Full Text Request