The effect of electrical stimulation of the hypothalamus and other brain areas on urea cycle enzymatic activities in the liver in rabbits--experimental studies on brain and liver interrelationship--.

Abstract

Changes in urea cycle enzymatic activities in the liver induced by intracerebral electrical stimulation in rabbits with chronically implanted electrodes in the hypothalamus, the thalamus, and the limbic area were studied in comparison with these activities in non-stimulated controls. In stimulating the ventromedial nucleus of the hypothalamus, the two-hour sessions were followed by significantly reduced activity in arginase and the arginine synthetase system in the liver, but the six-hour stimulation sessions were followed by normal range activity in these enzymes. In stimulating the lateral hypothalamic area, the two-hour sessions were followed by only slightly reduced activity in the arginine synthetase system in the liver. Stimulation of the center median nucleus of the thalamus, the medial area of the amygdala and the dorsal hippocampus produced no significant changes in urea cycle enzymatic activities in the liver. The possibility that ammonia metabolism in the liver may be modified through some functional linkage between the brain and the liver was suggested.