Development and regulation of ketogenesis in hepatocytes isolated from newborn rats.
The development of fatty acid metabolism was studied in isolated hepatocytes from newborn rats. Ketone-body production from oleate is increased 6-fold between 0 and 16 h after birth. This increase is related to an enhanced beta-oxidation rather than to a channeling of acetyl-CoA from the tricarboxylic acid cycle to ketone-body synthesis. The increase in oleate oxidation is not related to a decreased esterification rate, as the latter is already low at birth and does not decrease further. At birth, lipogenic rate is 2-3-fold lower than in fed adult rats and it decreases to undetectable values in 16 h-old rats. A 90% inhibition of lipogenesis in hepatocytes of newborn rats (0 h) by glucagon and 5-(tetradecyloxy)-2-furoic acid does not lead to an increased oxidation of non-esterified fatty acids. This suggests that the inverse relationship between lipogenesis and ketogenesis in the starved newborn rat is not responsible for the switch-on of fatty acid oxidation at birth. Moreover, ketogenesis from octanoate, a medium-chain fatty acid the oxidation of which is independent of carnitine acyltransferase, follows the same developmental pattern at birth as that from oleate.
D000818:Animals; D000831:Animals, Newborn / Q000378:metabolism*; D002210:Caprylates / Q000378:metabolism; D005260:Female; D066298:In Vitro Techniques; D007657:Ketone Bodies / Q000096:biosynthesis*; D007773:Lactates / Q000378:metabolism; D019344:Lactic Acid; D008055:Lipids / Q000096:biosynthesis; D008099:Liver / Q000166:cytology / Q000378:metabolism*; D019301:Oleic Acid; D009829:Oleic Acids / Q000378:metabolism; D051381:Rats; D011919:Rats, Inbred Strains
D002210:Caprylates; D007657:Ketone Bodies; D007773:Lactates; D008055:Lipids; D009829:Oleic Acids; D019301:Oleic Acid; D019344:Lactic Acid; C031492:octanoic acid