Tissue concentrations of free hexosamines and N-acetylhexosamines in rat liver

seen with noradrenaline, whereas dopamine had no effect. In all experiments endogenous ketone-body production was unchanged. We have therefore shown a small effect with adrenaline at supraphysiological concentrations on hepatic ketone-body production in both fed and 48h-starved rats. No real effect of noradrenaline or dopamine could be demonstrated, although only a small number of preparations have been examined. Heimberg et al. (1964) have also showed direct effects of the catecholamines on hepatic ketogenesis, using the isolated perfused liver preparation. Therefore most effects of catecholamines in uivo on ketonebody metabolism are probably due to lipolysis and increased supply of non-esterified fatty acids to the liver. However, catecholamines in vivo also induce a suppression of insulin secretion, and the effect of catecholamines on ketone-body production in hepatocytes from insulin-deficient animals remains to be investigated.