Effect of human kidney lipids on human kidney renin activity.

The major lipids of human kidney tissue were isolated by solvent extraction, and the lipid composition was determined by thin-layer chromatographic techniques. The positional distribution of fatty acyl groups in ethanolamine and choline phosphatides was determined after enzymatic hydrolysis. Major phosphatides were assayed for plasmalogen content. Triglycerides were characterized by argentation chromatography. The fatty acyl composition of these lipids was also determined. The effect of intact triglycerides, phospholipids, 1- and 2-monoacyl phosphatides and ether lipids on renin activity in vitro was determined by incubations with 3-[U 14 C]valyl tetradecapeptide renin substrate. Kidney triglycerides, 1-monoacyl and 2-monoacyl phosphatidylethanolamines and phosphatidylcholines significantly inhibited renin activity. The renin-inhibitory effect of these lipids was comparable to inhibition by hog kidney phospholipid inhibitor. The intact phospholipids and cholesterol potentiated human kidney renin activity. Phosphatidylserines and synthetic glyceryl ether lipids have no significant effect. These results indicate that lipid-induced inhibition of human renin activity does not require the ethanolamine moiety, acyl group unsaturation, or the presence of a hydroxyl group at the 2-position. Additionally, no specific structure-activity relationships can describe lipid-renin interactions.