Stimulated production of slow reacting substances by mercaptans from ionophore A 23187- induced mononuclear cells: Mercaptan structure-activity studies

Abstract

When isolated mononuclear cells from the peritoneal cavity of the rat are challenged with the ionophore, A 23187, slow reacting substance (SRS) is produced. SRS production is markedly enhanced by the addition of mercaptans to the incubations. In confirmation of previously published reports, this enhancement is dependent on the duration of a preincubation of the cells with the mercaptans before addition of the ionophore, a two minute preincubation being optimal. Quantitative structure-activity studies revealed that a variety of mercapto carboxylic acids, where the mercapto group was one or two carbon atoms removed from the carboxyl group, were all active in enhancing SRS production and the enhancement followed parallel dose response curves. A 4-mercapto acid, while weakly active, had a distinctly different dose response curve and cysteamine, which lacks a carboxyl function, was inactive. Preliminary characterization of the products of the incubations produced in the presence of different mercaptans has revealed that, while they all qualitatively meet the criteria of stability to alkali, lability in acid and destruction by arylsulfatase which are associated with slow reacting substance of anaphylaxis, there are quantitative differences in stability which suggest that the products may not be identical.