Influence of relaxin and insulin on the activity of adenylate cyclase in the myometrium of pregnant women with type 1 diabetes mellitus

The study of the influence of relaxin and insulin on the activity of adenylate clase (AC) in the myometrium of pregnant women showed that human relaxin 2 (10-9-10-8 M) causes a stronger stimulating effect on the enzyme activity than insulin. The activating effect of relaxin and insulin was potentiated by a non-hydrolyzable GTP analogue, guanylylimidodiphosphate (GIDP), in the myometrium of pregnant women, which indicates the participation of the stimulating GTP-binding protein (Gs-protein) in the realization of the effect of peptides. In the myometrium of pregnant women with type 1 diabetes mellitus under the action of relaxin, insulin and isoproterenol, a decrease in the sensitivity of AC activity to these hormones was found in comparison with these indicators in the myometrium of pregnant women. With the combined effect of peptides and GIDP in the myometrium of pregnant women with type 1 diabetes mellitus, a weakening of the potentiation of the GIDP effect of hormones on AC activity was observed, which may indicate a decrease in the coupling between receptors, Gs protein, and AC. The studies carried out allow us to conclude that in pregnant women with type 1 diabetes mellitus, the decrease in AC stimulation under the influence of these hormones is associated with a weakening of the Gs-protein function.