Changes in the enzyme activity of the myocardium and participation of the alpha-adrenergic and M-cholinergic systems in experimental isoprenaline myocardial hypertrophy.

With a view to clarifying the mechanisms of haemodynamic stress, as well as the role of some neurotransmitter systems in the pathogenesis of myocardial hypertrophy (MH), a complex of experiments was carried out with an MH model induced in rats by isoprenaline treatment and by applying the M-cholinolytic agent atropine and the alpha-adrenergic blocker phentolamine in a part of the experimental groups. The changes in the activity of some enzymes of myocardial metabolism, namely: glucose-6-phosphate dehydrogenase, pyruvate kinase, alpha-hydroxy-butyrate dehydrogenase, isocitrate dehydrogenase, malate dehydrogenase and creatine phosphokinase, were traced in 33 male Wistar rats. Considerable activation of glucose-6-phosphate dehydrogenase was found in the different experimental groups, suggesting the adaptive "anti-stress" character of this change. The results of the pathobiochemical studies presuppose the substantial participation of the alpha-adrenergic and of the M-cholinergic systems in the stage of compensated isoprenaline-induced myocardial hypertrophy.