Effect of chronic glucagon administration on lipoprotein composition in normally fed, fasted and cholesterol-fed rats.
Male adult Wistar rats received daily (at 9 a.m. and 5 p.m.) 10 micrograms of zinc-protamine glucagon by subcutaneous injection for 8 days. Plasma cholesterol levels were decreased by 36% in fed rats, 33% in cholesterol-fed rats and by 55% in fasted rats. Lipoproteins were separated into 22 fractions by ultracentrifugation using a density gradient. Glucagon administration decreased the cholesterol content in all lipoproteins except low density lipoprotein (LDL1) (1.006-1.040) and very low density lipoprotein (VLDL) from cholesterol-fed rats. The main decrease (-57 to -81%) was observed in 1.050-1.100 g/mL lipoproteins (LDL2 and HDL2), which contained a large amount of apo E, while HDL3 cholesterol was not affected. Triacylglycerol levels were decreased only in chylomicrons and VLDL (-70%) of fed and cholesterol-fed rats, while plasma and lipoprotein triacylglycerol levels were not changed in fasted rats treated with glucagon. In normally fed rats glucagon administration increased by 42% the fractional catabolic rate of [125I]HDL2 while the absolute catabolic rate appeared to be unchanged. Glucagon seems to be a potent hypolipidemic agent affecting mainly the apo E-rich lipoproteins. Its chronic administration limits lipoprotein accumulation which occurs upon cholesterol feeding.
Guettet
C
C
Unité de Recherches sur les Dyslipidémies et l'Atherosclérose, INSERM U 32 Hôpital Henri-Mondor, Créteil, France.
Rostaqui
N
N
Mathé
D
D
Lecuyer
B
B
Navarro
N
N
Jacotot
B
B
D000818:Animals; D001057:Apolipoproteins E / Q000097:blood; D002499:Centrifugation, Density Gradient; D002784:Cholesterol / Q000008:administration & dosage* / Q000097:blood; D008076:Cholesterol, HDL / Q000097:blood; D008078:Cholesterol, LDL / Q000097:blood; D015243:Cholesterol, VLDL / Q000097:blood; D002914:Chylomicrons / Q000097:blood; D005215:Fasting; D005934:Glucagon / Q000008:administration & dosage / Q000494:pharmacology*; D008074:Lipoproteins / Q000097:blood*; D008075:Lipoproteins, HDL / Q000097:blood; D053439:Lipoproteins, HDL2; D008297:Male; D010743:Phospholipids / Q000097:blood; D051381:Rats; D011919:Rats, Inbred Strains; D014280:Triglycerides / Q000097:blood
D001057:Apolipoproteins E; D008076:Cholesterol, HDL; D008078:Cholesterol, LDL; D015243:Cholesterol, VLDL; D002914:Chylomicrons; D008074:Lipoproteins; D008075:Lipoproteins, HDL; D053439:Lipoproteins, HDL2; D010743:Phospholipids; D014280:Triglycerides; D005934:Glucagon; D002784:Cholesterol