On the identification and biological properties of prostaglandin J2

Prostaglandin D2 spontaneously decomposes at physiological pH and temperature to 9-deoxy-delta 9-PGD2 (designated PGJ2). We developed a TLC procedure for the isolation of PGJ2 which was identified by both proton-NMR and mass spectrometry. Freshly prepared PGJ2 was active in inhibiting aggregation induced by ADP in citrated human platelet rich plasma. As reported by Fukushima et al. (1). PGJ2 was less active (x 0.1-0.25) than PGD2 as an inhibitor. Concentrations of PGJ2 that markedly inhibited aggregation of human platelets were generally incapable of inhibiting aggregation of rat or guinea pig platelets. Using a heterologous system of human platelets mixed with guinea pig plasma samples (2), it was shown that the ability of PGJ2 to inhibit platelet aggregation was lost immediately following intravenous injection in anesthetized guinea pigs. This apparent rapid uptake and/or degradation of PGJ2 might also explain why PGJ2 had no effect on blood pressure of anesthetized guinea pigs. PGJ2 was potent in inhibiting proliferation of cultured vascular smooth muscle cells, mouse melanoma cells and mouse fibroblasts. Less potent anti-proliferative effects were seen with two other degradation products of PGD2, one of which was the delta 12 metabolite reported (3,4) to be formed from PGJ2 in a reaction catalyzed by serum albumin.