Liver carnitine metabolism after partial hepatectomy in the rat: Effects of nutritional status and inhibition of carnitine palmitoyltransferase

This study examined the effects of partial hepatectony on hepatic carnitine and acylcarnitine concentrations in fed or 24 h-starved partially hepatectonized (PH) or sham-operated (SO) rats at 1 or 4 days after surgery. The ratio of free to esterified carnitine was low in fed PH rats at day 1 : the low ratio was increased to the SO value when mitochondrial fat oxidation was inhibited by 2-tetradecylglycidate. Starvation (24 h) increased plasma [non-esterified fatty acid] in PH or SO rats, the increases being greater at day 1 than at day 4. Hepatic [long-chain acylcarnitine] were also increased. These latter increases were a consequence of increased mitochondrial fat oxidation since they were not observed in PH or SO rats treated with 2-tetradecylglycidate. Whereas the starvation-induced increase in long-chain acylcarnitine was associated with increased [ketone body] in livers of SO rats at both day 1 and day 4 after surgery, [ketone body] was inappropriately low for the steady-state long-chain [acylcarnitine] in livers of PH rats at the first post-operative day. This was not a consequence of a decrease in [total carnitine] in the liver. The results are discussed with reference to the role of the liver in determining the relative proportions of the fat fuels available for extrahepatic tissues and the effects of liver cell proliferation on hepatic triacylclycerol metabolism.