Short and long-term effects of streptozotocin on dietary cholesterol absorption, plasma lipoproteins and liver lipoprotein receptors in RICO rats.
Adult male genetically hypercholesterolemic RICO rats were studied 6 and 28 days after streptozotocin (STZ) administration together with untreated RICO controls. The absorption coefficient of dietary cholesterol was determined using dual-isotope blood ratio method. Plasma lipoproteins as well as fecal neutral sterols and bile acids were analysed at both experimental times. Liver lipid parameters were measured and lipoprotein receptors (LDLr, SR-BI and HB2) were assayed by immunodetection. Six days after STZ administration, dietary cholesterol absorption was more efficient (+49%) in treated rats than in controls, and stayed higher (+68%) in the diabetic rats sacrificed at day 28. Fecal neutral sterol elimination decreased soon after STZ administration (by 35% at day 6), due to a higher cholesterol absorption coefficient, then increased to control level at day 28, due to installed diabetes-induced hyperphagia. Comparison of the lipoprotein profiles indicated that the concentration of HDL1. which is typically high in control Rico rats, fell significantly in diabetic rats at both experimental times, whereas that of HDL2 increased only at day 28. In diabetic rats, an early and strong enhancement of the hepatic expression of SR-BI appeared at day 6 (+415%) and persisted at day 28, but at a lesser extent (+85%). The expression of LDLr and HB2 was unchanged at day 6, but was significantly modified at day 28 (+140% for LDLr and -50% for HB2). These data show that streptozotocin-induced diabetes in Rico rats results in modifications of the expression of liver lipoprotein receptors which can contribute to alterations of the lipoprotein profile.
Milliat
F
F
Laboratoire de Physiologie de la Nutrition. Université Paris-Sud, Centre d'Orsay, France.
Gripois
D
D
Blouquit M-E
Férézou
J
J
Sérougne
C
C
Fidge
N H
NH
Lutton
C
C
D000818:Animals; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D001647:Bile Acids and Salts / Q000378:metabolism; D001786:Blood Glucose / Q000378:metabolism; D015153:Blotting, Western; D001835:Body Weight / Q000187:drug effects; D002791:Cholesterol, Dietary / Q000493:pharmacokinetics*; D003921:Diabetes Mellitus, Experimental / Q000097:blood / Q000378:metabolism; D005243:Feces / Q000737:chemistry; D006937:Hypercholesterolemia / Q000097:blood / Q000235:genetics*; D007408:Intestinal Absorption / Q000187:drug effects*; D008074:Lipoproteins / Q000097:blood*; D008099:Liver / Q000187:drug effects / Q000378:metabolism; D008297:Male; D009929:Organ Size / Q000187:drug effects; D051381:Rats; D018110:Receptors, Lipoprotein / Q000097:blood*; D013261:Sterols / Q000378:metabolism; D013311:Streptozocin / Q000494:pharmacology*
D000900:Anti-Bacterial Agents; D001647:Bile Acids and Salts; D001786:Blood Glucose; D002791:Cholesterol, Dietary; D008074:Lipoproteins; D018110:Receptors, Lipoprotein; D013261:Sterols; D013311:Streptozocin