Effect of catecholamines on the metabolic fate of nonesterified fatty acids in isolated hepatocytes from newborn rats.
Isolated hepatocytes from newborn rats are able to produce ketone bodies from added medium-chain and long-chain fatty acids. Carnitine enhances the rate of ketone body synthesis from palmitate as well as from caprinoate. The 3-OHB/AcAc ratios indicate a highly reduced state of the mitochondrial redox carriers in the presence of both fatty acids and carnitine. Ketogenesis from palmitate accounts for about 90% of the total beta-oxidation. At recovery of 95% of the radioactivity two thirds of totally fatty acid uptake are channeled into esterification, whereas the remainder is oxidized. alpha- and beta-agonists stimulate glycogen degradation and glucose release and reduce net lactate production in hepatocytes from newborn rats. The (1-14C)-palmitate uptake is not altered by alpha- and beta-agonists. Phenylephrine significantly enhances 14CO2 production from (1-14C)-palmitate. Neither of the agonists affects the rate of esterification or of ketone body production with palmitate as substrate. Isoproterenol, however, stimulates ketogenesis from caprinoate even in the presence of optimal carnitine concentrations.
D000818:Animals; D000831:Animals, Newborn; D002331:Carnitine / Q000494:pharmacology; D002395:Catecholamines / Q000494:pharmacology*; D005230:Fatty Acids, Nonesterified / Q000378:metabolism*; D005947:Glucose / Q000378:metabolism; D066298:In Vitro Techniques; D007545:Isoproterenol / Q000494:pharmacology; D007657:Ketone Bodies / Q000096:biosynthesis; D008099:Liver / Q000378:metabolism*; D008112:Liver Glycogen / Q000378:metabolism; D051381:Rats; D011919:Rats, Inbred Strains; D013997:Time Factors
D002395:Catecholamines; D005230:Fatty Acids, Nonesterified; D007657:Ketone Bodies; D008112:Liver Glycogen; D005947:Glucose; D007545:Isoproterenol; D002331:Carnitine