An antiserum against 9,11-azo-15-hydroxy-prosta-5,13-dienoic acid recognises and binds prostaglandin endoperoxides

Abstract

THE prostaglandin endoperoxides PGG₂ and PGH₂, derived from arachidonic acid, are transient regulators in mammalian cells^1–4. On formation, the endoperoxides are rapidly converted to PGF_2α, PGE₂, PGD₂, and their 15-keto-PG metabolites; to 12-L-hydroxy-5,8,10-heptadecatrienoic acid (HHT) and malonaldehyde⁵; to thromboxane A₂ (refs 6, 7); and to PGI₂ (prostacyclin or PGX; ref. 8). The enzymatic composition of each tissue governs the nature and extent of these conversions. By their direct influence and as precursors for other prostaglandins, the endoperoxides are primary cellular regulators; unfortunately, their short half life and intrinsic instability makes direct determination of PGH₂ related phenomena difficult. By using as the hapten a stable mimic⁹, stereochemically similar to the physiologically authentic endoperoxides, we have prepared antibodies which recognise and bind PGG₂ and PGH₂. Enzymatic and chemical conversion of the endoperoxides and their pharmacological influence on platelet aggregation in vitro are retarded by these antibodies.