Effects of chronic glucagon administration on cholesterol and bile acid metabolism.
Male adult Wistar rats received daily, at 9 a.m. and 5 p.m., 10 micrograms of Zn-protamine glucagon for 21 days by subcutaneous injections. The blood glucose level was not significantly modified. Cholesterol and triacylglycerol levels were decreased by 40 and 70% in plasma but not in the liver. The rates of cholesterol turnover processes were determined in vivo with an isotope balance method. Internal secretion of cholesterol (13.8 +/- 0.5 mg/day per rat in control rats and 22.4 +/- 0.9 mg/day per rat in glucagon-treated rats) and cholesterol transformation into bile acids were strikingly increased by chronic administration of glucagon. Biliary secretion rates of bile acids measured by a wash-out method were increased by 139%, while the intestinal bile acid pool was not changed. The enterohepatic cycle number was increased from five per day in control rats to nine per day in glucagon-treated rats. An increased turnover rate of the exchangeable cholesterol would explain the hypocholesterolemic effect of glucagon.
Guettet
C
C
Unité de Recherches sur les Dyslipidémies et l'Athérosclérose, INSERM U 32, Hôpital Henri-Mondor, Créteil, France.
Mathe
D
D
Riottot
M
M
Lutton
C
C
D000085:Acetates / Q000378:metabolism; D000818:Animals; D001647:Bile Acids and Salts / Q000378:metabolism*; D002784:Cholesterol / Q000378:metabolism*; D002791:Cholesterol, Dietary / Q000378:metabolism; D005243:Feces / Q000032:analysis; D005934:Glucagon / Q000494:pharmacology*; D007328:Insulin / Q000494:pharmacology; D007413:Intestinal Mucosa / Q000378:metabolism; D007422:Intestines / Q000187:drug effects; D008099:Liver / Q000187:drug effects / Q000378:metabolism; D008297:Male; D051381:Rats; D011919:Rats, Inbred Strains; D012016:Reference Values
D000085:Acetates; D001647:Bile Acids and Salts; D002791:Cholesterol, Dietary; D007328:Insulin; D005934:Glucagon; D002784:Cholesterol