Adjuvant arthritic rat serum enhances HETE1 biosynthesis.

The effect of serum from adjuvant arthritic rats in the chronic inflammatory stage, on lipoxygenase activity in either rat peritoneal macrophages, intact rabbit platelets or the cytoplasmic fraction of horse platelet homogenates was studied. All preparations produced significantly more HETE from exogenous arachidonic acid in the presence of arthritic serum than normal serum. This effect was known not to be associated with the lower albumin level in arthritic serum, and it was specific for the lipoxygenase pathway of arachidonic acid metabolism as there was no effect on cyclo-oxygenase activity. The presence of an arthritic serum factor(s), with a molecular weight in the range of 100,000 as indicated by gel-filtration experiments, which specifically enhances the synthesis of HETE, is proposed.