The contribution of hepatic metabolism to diet-induced thermogenesis.

In order to examine the possible contribution of the liver to diet-induced thermogenesis, we examined the metabolism of hepatocytes from rats that had been fed a varied choice of highly palatable human food items ("cafeteria feeding"). Liver cells derived from cafeteria-fed rats that had been fasted for 20 hours showed marked increases in rates of respiration and gluconeogenesis in the presence of glycerol or sorbitol. These cells were also much less sensitive to the inhibitory effects of rotenone than were hepatocytes of control animals. hepatocytes from fasted cafeteria-fed rats also demonstrated a substantially enhanced rate of fatty acid oxidation and ketogenesis, which did not appear to be correlated with cellular demands for adenosine triphosphate (ATP). This apparent fall in metabolic efficiency was confirmed by calorimetric studies, which indicated augmented cellular heat production. These changes in hepatic metabolism, associated with cafeteria-feeding, suggest that the liver may have a significant role in diet-induced thermogenesis.