[Involvement of adenylyn cyclase signaling mechanisms in relaxing effect of relaxin and insulin on the rat uterus, trachea and human myometrium].

Participation of adenylyl cyclase signaling mechanisms of relaxin and insulin action in their regulating influence on the process of relaxation of the rat uterine and tracheal smooth muscles and human myometrium was shown. The study was based on the discovery of novel adenylyl cyclase signaling mechanisms of relaxin and insulin action in the muscle of vertebrates which involve: receptor --> Gi protein (betagamma dimer) --> phosphatidylinositol-3-kinase --> protein kinase Csigma (zeta) --> Gs protein --> adenylyl cyclase --> cAMP. In the rat uterus, trachea and human myometrium, relaxin, insulin and isoproterenol induced relaxation of KCl-contraction. The order of efficiency of the agents based upon their ability to induce the inhibiting effect on the KCl-contraction was as follows: relaxin = insulin > isoproterenol. The hormones induce activating effect on adenylyl cyclase leading to production of cAMP in the rat uterine and tracheal smooth muscles and human myometrium. It is shown that cAMP reproduces relaxing effect of the hormones under study. Thus, the involvement of novel adenylyl cyclase signaling mechanisms of relaxin and insulin action in realization of their relaxation effect on rat uterus, trachea and human myometrium was revealed for the first time.