EFFECTS OF GLUCOCORTICOIDS ON THE DISTRIBUTION AND MOBILIZATION OF ARACHIDONIC-ACID IN FAT-CELL GHOSTS

The prostaglandin synthesizing enzymes were found to be present in fat cell ghosts isolated from rabbit adipose tissue. Prostaglandin E2 (PGE2) and PGF2 were synthesized by ghosts after stimulation with adrenocor‐ticotrophic hormone (ACTH). Indomethacin was found to inhibit this synthesis but not the synthesis of lipoxygenase products. When fat cell ghosts were stimulated by ACTH, fatty acid release was observed from both neutral lipids and phospholipids. The arachidonic acid (AA) pool within the ghosts was identified: approximately 90% was present in the phospholipid fraction, 8.5% in the neutral lipids and 1.5% unbound. The glucocorticoids were found to stimulate incorporation of [14C]‐AA into neutral lipids and inhibit its incorporation into phospholipids. When fatty acid release was stimulated with ACTH, the glucocorticoids were found to inhibit the mobilisation of [14C]‐AA from the phospholipids and enhance its release from the neutral lipids. The glucocorticoids inhibit prostaglandin formation in fat cell ghosts. 1979 British Pharmacological Society