RELATIONSHIP BETWEEN CHEMICAL STRUCTURE AND PLATELET-AGGREGATION ACTIVITY OF PROSTAGLANDINS

The finding that prostaglandin E1 inhibits ADP-induced platelet aggregation in citrated platelet-rich rat-blood plasma, whereas prostaglandin E2 stimulates it, has led to an investigation into the potencies of the opposing effects in relation to each other by examining mixtures of prostaglandins E1 and E2 at different concentrations. It has been found that the relationship between the extent of platelet aggregation, expressed in percentages of the maximum decrease in absorbance in the control (% max. Δ A), and the molar concentration of prostaglandins E1 and E2 can be written as: % max. ΔA = -494 -99 log [PGE1 + 26 log [PGE2]. In order to gain information on the relationship between chemical structure and biological activity, 23 prostaglandins and the methyl esters of some of them were examined for their effects on platelet aggregation in citrated platelet-rich ratblood plasma. It has been found that the CO groups at the ring and in the carboxyl group, as well as the distance between them, are essential, as is the hydroxyl group at C-15. © 1969.