HYPERCALORIC LIPID AND GLUCOSE-INFUSION REDUCES THE MITOCHONDRIAL RESPIRATORY ACTIVITY IN THE REGENERATING RAT-LIVER

In order to evaluate the liver mitochondrial response to an increased energy load, eight groups of rats were studied: a control group (no su rgery), a sham-operated group, and 6 groups that had undergone partial hepatectomy (PH). The PH rats either had no infusion following surger y, saline, isocaloric lipid, hypercaloric lipid, isocaloric glucose or hypercaloric glucose infusion. After isolation of liver mitochondria 6, 12, 18 and 24 h after surgery states 3 and 4 of respiration were me asured in vitro in the presence of succinate. State 3 and 4 mitochondr ial respiration was higher in the sham-operated rats 6 h after surgery than in the control animals, and a gradual decrease towards control v alues occurred in the 12-24 h period following surgery. Results in mit ochondria from PH rats showed variable results, in most cases both Sta te 3 and 4 respiration was higher after PH, while the respiratory cont rol index in general was lower. State 3 respiration was significantly increased in the PH isocaloric lipid and glucose infused groups 6, 12 and 18 h, but not 24 h after partial hepatectomy. The PH hypercaloric glucose and hypercaloric lipid infused rats showed decreases in the li ver mitochondrial oxygen consumption after 6, 12 and 18 h of liver reg eneration, this was more pronounced after hypercaloric lipid infusion. These results suggest that, in vitro, the surgery tends to increase S tatus 3 and Status 4 mitochondrial respiration. The hypercaloric paren teral nutrition, both lipid and glucose based, significantly decreased liver mitochondrial oxygen consumption in partially hepatectomized ra ts, particularly in the first hours of liver regeneration, with restor ation 24 h after surgery.