Regulation of plasma lipid levels by plasma viscosity in nephrotic rats.
The viscosity of the extracellular medium of cultured hepatocytes has been shown to be a regulator of the secretion and synthesis of very low-density lipoproteins (Yedgar et al., J. Biol. Chem. 257: 2188-2192, 1982). At present, the role of plasma viscosity in regulation of plasma lipoprotein levels was examined in vivo using nephrotic hyperlipidemic rats. Plasma viscosity was increased by injection of macromolecules: simultaneously with induction of nephrosis by aminonucleoside; and after the lipid level had reached its maximum. In experiment 1 the elevation of plasma viscosity (which persisted for at least 2 days) delayed the development of the hyperlipidemia by at least 2 days. In experiment 2 increasing the plasma viscosity reduced plasma triglyceride and cholesterol levels by 70 and 40%, respectively, within 2 days. The hyperlipidemia was accompanied by increased plasma viscosity. The contribution of lipoproteins to plasma viscosity was 27% in the nephrotic-hyperlipidemic rats, compared with 4% in normal rats. It is suggested that plasma viscosity regulates lipoprotein levels in vivo concordant with the observation in cultured hepatocytes.
D000818:Animals; D001809:Blood Viscosity; D002784:Cholesterol / Q000097:blood; D006949:Hyperlipidemias / Q000209:etiology / Q000503:physiopathology; D008055:Lipids / Q000097:blood*; D008074:Lipoproteins / Q000097:blood*; D008297:Male; D009404:Nephrotic Syndrome / Q000097:blood / Q000139:chemically induced / Q000503:physiopathology*; D011692:Puromycin Aminonucleoside; D051381:Rats; D011919:Rats, Inbred Strains; D014280:Triglycerides / Q000097:blood
D008055:Lipids; D008074:Lipoproteins; D014280:Triglycerides; D011692:Puromycin Aminonucleoside; D002784:Cholesterol