Aggregation of polymorphonuclear leucocytes (PMNs) by leukotriene B4: Effects of cyclooxygenase products and metabolic inhibitors

Abstract

Leukotriene B₄ isomer III (LTB₄) stimulates the aggregation of rat PMNsin vitro. The effects of deoxyglucose, iodoacetate, dinitrophenol, cyclohexamide, colchicine, prostaglandins and thromboxane B₂ (TXB₂) on aggregation were examined. The results demonstrate that, first, aggregation is an active process, the energy being supplied by glycolysis and not mitochondrial respiration. The response can be elicited in the absence of extracellular glucose. Synthesis of protein does not occur during aggregation. An intact microtubular system is required for the expression of a full aggregation response. Prostaglandins E₁, E₂, F_2α and TXB₂, products of the cyclooxygenase pathway of arachidonic acid metabolism, partially inhibit LTB₄-induced aggregation by a mechanism which has not yet been elucidated. The prostaglandins and TXB₂ themselves do not promote aggregation.