Effects of some naturally occurring prostaglandins of the D-, E-, and I-type and synthetic analogues on adenylate cyclase of human fat cell ghosts.

The effects of various prostaglandins originating from arachidonic acid (prostaglandin E2, D2, I2) as well as of methylated analogues of prostaglandin E2 (16,16-dimethyl prostaglandin E2 and 15-S-methyl prostaglandin E2) on the human fat cell adenylate cyclase were studied. In addition, the stable breakdown product of prostaglandin I2, prostaglandin 6-keto-F1-alpha, was tested for activity. Prostaglandin E2 and its methylated analogues as well as prostaglandin D2 and I2 were active stimulators of the human fat cell enzyme. The stable breakdown product of prostaglandin I2 (prostaglandin 6-keto-F1-alpha) which is biologically inactive had no stimulatory effects, suggesting that stimulation of the human fat cell function. The stimulatory action of prostaglandin D2 is consistent with the elevation of cAMP-levels induced by this compound in intact fat cells. It is concluded that the stimulatory effects of prostaglandins on the human fat cell adenylate cyclase are related to their stimulatory effects upon lipolysis.