Effect of glucocorticoid hormones on fatty acid mobilization and re-esterification in rat adipose tissue.
1. The effect of dexamethasone and cortisol on fatty acid mobilization and re-esterification has been studied in intact adipose tissue and isolated fat cells of the rat. 2. Dexamethasone added in vitro inhibited both the re-esterification of mobilized free fatty acids and the esterification of palmitate in the medium. 3. Under several conditions (low concentrations of dexamethasone, cortisol at a high concentration, with tissue from starved animals), steroid-induced release of free fatty acids could be accounted for by decreased re-esterification only, overall lipolytic activity remaining unmodified. At higher concentrations of dexamethasone, however, stimulation of lipolytic activity also occurred. 4. Decreased re-esterification produced by dexamethasone was observed in the total absence of glucose from the incubation medium. Further, dexamethasone stimulated the disappearance of prelabelled [(14)C]glycogen from the tissue. 5. The evidence presented suggests that mobilization of free fatty acids induced by glucocorticoid hormones under physiological conditions is primarily due to a decrease of the re-esterification rate rather than to lipase activation.
D000273:Adipose Tissue / Q000187:drug effects / Q000378:metabolism*; D000818:Animals; D002247:Carbon Isotopes; D003907:Dexamethasone / Q000494:pharmacology*; D005230:Fatty Acids, Nonesterified / Q000378:metabolism*; D005990:Glycerol / Q000378:metabolism; D006003:Glycogen / Q000378:metabolism; D006854:Hydrocortisone / Q000494:pharmacology*; D066298:In Vitro Techniques; D008297:Male; D010169:Palmitic Acids / Q000378:metabolism; D051381:Rats
D002247:Carbon Isotopes; D005230:Fatty Acids, Nonesterified; D010169:Palmitic Acids; D003907:Dexamethasone; D006003:Glycogen; D005990:Glycerol; D006854:Hydrocortisone