Effect of excess and deficiency of vitamin A on the utilization of FFA by liver and skeletal muscle.
Fatty acid metabolism in liver and skeletal muscle has been studied in rats treated with high doses of vitamin A and in those made vitamin A-deficient. Ingestion of 30,000 IU of vitamin A for two days resulted in increased incorporation of palmitate-1-14C into triglycerides but not into phospholipids. Accumulation of hepatic triglycerides was observed in vitamin A-fed rats. Deficiency of vitamin A did not cause any change in the triglyceride or phospholipid content of the liver. The rate of hepatic fatty acid oxidation and ketogenesis was markedly increased in vitamin A-fed rats. The experimental evidence indicated that vitamin A may have a stimulatory effect on these processes apart from that exerted by the high plasma FFA level in vitamin A-fed rats. Oxidation of palmitate-1-14C into C32 by skeletal muscle (latissimus dorsi) was also increased as a result of vitamin A administration. Vitamin A deficiency did not cause any change in fatty acid oxidation by liver and skeletal muscle. Hepatic palmitoyl-CoA synthetase activity was decreased in vitamin A-deficient rats. The results presented suggest that vitamin A may be required for the uptake and utilization of fatty acids by liver and akeletal muscle.
D000090:Acetoacetates / Q000378:metabolism; D000818:Animals; D002245:Carbon Dioxide / Q000378:metabolism; D005230:Fatty Acids, Nonesterified / Q000378:metabolism*; D008099:Liver / Q000201:enzymology / Q000378:metabolism*; D008297:Male; D009132:Muscles / Q000378:metabolism*; D010084:Oxidation-Reduction / Q000187:drug effects; D010168:Palmitates / Q000378:metabolism; D010743:Phospholipids / Q000378:metabolism; D051381:Rats; D013268:Stimulation, Chemical; D014280:Triglycerides / Q000378:metabolism; D014801:Vitamin A / Q000494:pharmacology*; D014802:Vitamin A Deficiency / Q000378:metabolism*
D000090:Acetoacetates; D005230:Fatty Acids, Nonesterified; D010168:Palmitates; D010743:Phospholipids; D014280:Triglycerides; D014801:Vitamin A; D002245:Carbon Dioxide