Eight experimental pigs, each weighing 80 kg, received intramuscular doses of swine growth hormone (GH).40–45 min after the GH injection the experimental and control pigs were killed by electric shock. After killing, their thoraxes were opened and preparations of coronary arteries for testing contractility and concentration of bioelements were taken. Heart samples (part of the left ventricle) were taken for bioelement and morphological tests. The force of contraction of coronary arteries preparations was registered every 3 min by micromechanographic method in isometric regime and expressed in percentage terms. The concentration of bioelements (Zn, Cu, Mn, Mg, Ca) in coronary artery and heart was assessed by atomic absorption spectophotometer 503 Perkin-Elmer (USA). Cardiomyocytes contractility was studied by polarized microscopy. The research findings show the effect of GH on the contractility of smooth muscles of coronary arteries and cardiomyocytes is associated with the ability of GH to affect changes in the concentration of bioelements in the vascular and cardiac tissues and to modulate the adrenoreceptors. The changes in the concentration of bioelements, especially Mn and Ca, are in close correlation with contractility of coronary arteries and cardiomyocytes.