Mitotic activity of regenerating rat liver following stimulation with alpha- and beta-adrenoreceptors

A study was made of the effect of stimulating alpha- and beta-adrenoreceptors on the mitotic activity of the rat regenerating liver following resection. Mesaton, a stimulator of alpha-adrenoreceptors, and isadrin, a stimulator of beta-adrenoreceptors, in a dose of 0.2 mg/kg were injected one hour before liver resection or 30 min, 8 and 24 h after operation. In all experimental groups, mesaton gave rise to an increase in the mitotic index without lowering the coefficient of the mitotic phases. The least pronounced stimulating effect was attained when mesaton was injected 9 hours after partial hepatectomy. Isadrin reduced the mitotic activity as judged from the decrease of the coefficient of the phases and augmentation of the number of binuclear cells. The experiments confirmed a previously advanced assumption that stimulation of alpha-adrenoreceptors favours while that of beta-adrenoreceptors reduces cell proliferation.