Partition of Unesterified Fatty Acids in Normal and Nephrotic Syndrome Serum and Its Effect on Serum Electrophoretic Pattern1

Abstract

The electrophoretic pattern of serum in nephrotic syndrome is marked by decreased concentrations of albumin and elevated concentrations of alpha2- and beta-globulins. A large portion of excess lipid in nephrotic serum migrates at pH 8.6 in alpha2 region, whereas normally major part of lipid is found in beta position. This abnormal finding has never been adequately explained. Thus, Swahn remarks that the electrophoretic separation of alpha2- from beta-globulin in nephrotic sera is often poor and it is difficult to decide whether there is a pathological fraction migrating quicker than normal beta lipoprotein (1). Unesterified fatty acids (UFA) have been recently demonstrated to be of considerable importance in lipid transport and metabolism (2). In normal serum these acids are generally considered to be predominantly carried by albumin. However, Gordon (3) and others (4-6) have shown that UFA can increase electrophoretic mobility of serum lipoproteins when liberated in vivo by heparin-released lipase or when added directly to serum in vitro. It was inferred by above investigators that at these high levels, a significant fraction of UFA became associated with lipoproteins, thereby increasing their negative electrostatic surface charge. The present paper reports on direct measurements of partition of UFA resulting from competitive binding of UFA by albumin and components of serum. The distribution of UFA in normal sera was compared