Acetyl-CoA:1-O-alkyl-sn-glycero-3-phosphocholine acetyltransferase (lyso-PAF AT) activity in cortical and medullary human renal tissue

Platelet-activating factor (PAF) is one of the most potent inflammatory mediators. It is biosynthesized by either the de novo biosynthesis of glyceryl ether lipids or by remodeling of membrane phospholipids. PAF is synthesized and catabolized by various renal cells and tissues and exerts a wide range of biological activities on renal tissue suggesting a potential role during renal injury. The aim of this study was to identify whether cortex and medulla of human kidney contain the acetyl-CoA:1-O-alkyl-sn-glycero-3-phosphocholine acetyltransferase (lyso-PAF AT) activity which catalyses the last step of the remodeling biosynthetic route of PAF and is activated in inflammatory conditions. Cortex and medulla were obtained from nephrectomized patients with adenocarcinoma and the enzymatic activity was determined by a trichloroacetic acid precipitation method. Lyso-PAF AT activity was detected in both cortex and medulla and distributed among the membrane subcellular fractions. No statistical differences between the specific activity of cortical and medullary lyso-PAF AT was found. Both cortical and medullary microsomal lyso-PAF ATs share similar biochemical properties indicating common cellular sources.