A COMPARISON OF THE BIOLOGICAL ACTIVITIES OF FOUR PROSTAGLANDINS.

The biological activities of prostaglandins E(1), E(2), E(3) and F(1alpha) have been compared. Prostaglandins E(1), E(2), E(3) were qualitatively similar; E(1) and E(2) were about equiactive, but E(3) was less active on all preparations. Prostaglandin F(1alpha) was a less potent vasodilator than E(1) on the cat gastrocnemius muscle blood flow and skin blood flow and a less potent depressor drug on rabbit blood pressure. On the rabbit isolated jejunum F(1alpha) was twice as active as E(1) but on the guinea-pig isolated ileum E(1) was about forty times more active than F(1alpha). One qualitative difference between these prostaglandins was observed; on the rabbit fallopian tube in vivo prostaglandins of the E series decreased both the tone and the peristalsis of the tube whereas prostaglandin F(1alpha) increased tubal tone.