Hypoandrogenism Inhibits Erectile Function By Downreluating The Expression Of G-Protein-Coupled Receptor Kinase Interactor-1 (GIT1) In Rats Penile Corpus Cavernosum

Objective: To explore the influence of hypoandrogenism on G-protein-coupled receptor kinase interactor-1(GIT1)and its connection to erectile function.Methods: Thirty male Sprague Dawley(SD)rats,aged eight weeks,were distributed at random into five groups: the sham-operated group(control),the castration group(castration),the testosterone supplement after castration group(cast+T),the castration + empty vector lentivirus transfection group(cast +empty trans),and the castration + lentiviral transfection group(cast + trans).The sham operation group cut the scrotal skin of rats,and the other group removed testis and epididymis.After castration,cast+T group rats were injected with testosterone propionate at 3mg/kg subcutaneously every day,and other groups were injected with the same amount of vegetable oil in the same way.Four weeks after castration,a lentivirus carrying the GIT1 gene was injected into the middle of rats penile corpus cavernosum.One week after transfection,ICPmax/MAP,serum testosterone,NO,GIT1,e NOS,p-e NOS,and the interaction between e NOS and GIT1 were assessed in the rats.Results: The serum testosterone level in castration group(1.52 ± 0.18nmol/L)was significantly lower than that in sham-operated group(21.92±1.71nmol/L)and testosterone replacement group(22.61±1.96 nmol/L).The ICPmax/MAP was considerably decreased after castration(0.34±0.02,3 V;0.40±0.01,5 V)compared with the sham-operated group(0.56±0.03,3 V;0.67±0.03,3 V)and testosterone replacement group(0.57±0.03,3 V;0.65±0.03,5 V);After overexpression of GIT1,ICPmax/MAP in lentivirus transfection(0.43±0.02,3 V;0.53±0.03,5 V)group was significantly increased compared with the castrated group(0.34±0.02,3 V;0.40±0.01,5 V)(P<0.01).The expression of GIT1,p-e NOS,NO and GIT1-e NOS interaction in rats penile corpus cavernosum were significantly decreased in castration group compared with sham-operated group and testosterone replacement group(P<0.05).The expression of GIT1,p-e NOS,NO and GIT1-e NOS interaction in lentivirus transfection group were significantly increased compared with castrated group(P<0.05).Conclusion: Hypoandrogenism inhibits erectile function in rats by reducing the expression of GIT1 and the protein interaction between GIT1 and eNOS.