[Effect of DL-carnitine and gamma-butyrobetaine hydroxylase inhibitor 3-(2,2,2-trimethylhydrazinium) propionate on isoproterenol-induced changes in the metabolism of the rat myocardium].

3-(2,2,2-trimethyl hydrazinium) propionate (THP) is known as an inhibitor of gamma-butyrobetaine hydroxylase in rat liver tissue. At the same time, THP, administered per os at a dose of 100 mg/kg within 10 days, prevented the isoproterenol-induced (subcutaneously, 50 mg/kg) acylcarnitine accumulation. This effect of THP, accompanied by a distinct decrease of free carnitine in rat myocardium, occurred due to inhibition of carnitine biosynthesis from gamma-butyrobetaine. THP protected the myocardium energetics against isoproterenol action as the drug prevented the acylcarnitine accumulation. Although D,L-carnitine (200 mg/kg, per os, 10 days) inhibited also the isoproterenol-stimulated acylcarnitine accumulation in rat myocardium and fatty acids of blood serum, in did not exhibit any favourable effect on myocardium bioenergetics. Inefficiency of D,L-carnitine as cardioprotective drug may be a result of intensification of fatty acids metabolism occurring simultaneously with isoproterenol-mediated myocardium ischemia. Use of inhibitors of carnitine-dependent oxidation of fatty acids oxidation (as exemplified by THP) in order to correct myocardium metabolism is of importance especially in relation to impairing effects caused by catecholamines.