[Effect of insulin on cardiac contractility (author's transl)]

The effects of insulin on contractile activity of isolated heart muscle have been studied in the rat's right ventricle. The method of the isolated organ bath was used with Tyrode as perfusion liquid with constant carbogen bubbling. The addition of insulin to the bath (0.3 U/ml) increased the contractile power. Contractility increase, induced by adrenaline and CaCl2, was reduced by insulin. This decrease of adrenaline activity became clearer after partial blocking of beta-receptors with pindolol. Glucose determinations in the bath also showed an insulin-adrenaline antagonism. Insulin behaved as a partial agonist versus adrenaline at the beta-receptors site.