Biological activities of 17-phenyl-18,19,20-trinorprostaglandins.

In a number of assay systems, some 17-phenyl-trinor-prostaglandins were similar in activity and potency to the corresponding parent prostaglandin. In others, the 17-phenyl analogs appeared several times more potent. In the hamster antifertility assay, which is considered to measure luteolytic activity, 17-phenyl-18,19,20-trinor prostaglandin F2alpha was about 90-times PGF2alpha in potency. Rat blood pressure responses to 17-phenyl analogs were significant. The 17-phenyl-trinor PGF2alpha pressor potency was 5 times that of PGF2alpha. The 17-phenyl-trinor PGE2 blood pressure response was atypical since a pressor rebound phenomenon followed the expected depressor response. Lastly, 17-phenyl-trinor PGF2alpha was more potent than PGF2alpha in synchronizing the estrous cycle in beef cows.