6β-prostaglandin i-1

6α-Prostaglandin I1 (6α-PGI1) is a stable Prostaglandin I2 (PGI2) analog resistant to hydrolysis in aqueous solutions. It promotes cyclic AMP accumulation in human thyroid slices and cells in a concentration-dependent manner but is about 10-fold less potent than the β-isomer and 100-fold less potent than PGI2 in eliciting this response. 6α-PGI1 exhibits an IC50 of 350 ng/ml for inhibition of ADP-induced platelet aggregation, nearly 900-fold higher than that of PGI2 (0.4 ng/ml).

6β-PGI1 is a stable PGI2 analog resistant to hydrolysis in aqueous solutions. 6β-PGI1 has a much longer half-life than PGI2, but a greatly reduced molar potency for receptor mediated function. 6β-PGI1 has a Kact for adenylate cyclase in NCB-20 cells of 4.2 μM compared with 18 nM for PGI2. The potency for vasodilation and inhibition of platelet aggregation is about 1% of PGI2.