Glucocorticoid effect on the prostaglandin system in fat tissue.

A prostaglandin-mediated vasodilatation accompanies lipolysis in rabbit subcutaneous adipose tissue. Prostaglandin-synthetase inhibitors, like aspirin and indomethacin, reduced the prostaglandin content of the fat tissue during lipolysis and the functional vasodilatation but did not inhibit lipolysis itself. Anti-inflammatory steroids such as hydrocortisone and prednisolone inhibited vasodilatation but did not reduce the prostaglandin content of the fat tissue during lipolysis. As the steroids did not directly inhibit prostaglandin-induced vasodilatation, nor did they interfere with lipolysis, it seems likely that they inhibit the prostaglandin-mediated vasodilation by preventing the release of prostaglandin from the fat cells after formation. This suggestion is supported by the finding in vitro that indomethacin reduced the prostaglandin content of fat tissue and the incubation medium. On the other hand, steroids caused an increase in the prostaglandin content of the fat tissue while the prostaglandin leaking into the medium was significantly reduced.