Time course of changes in rat serum lecithin-cholesterol acyl-transferase activity and high-density-lipoprotein composition during the consumption of two different low-protein diets followed by a balanced diet.
We studied the effects of low-protein diets on high-density-lipoprotein (HDL) composition and checked whether the changes observed were correlated with lecithin-cholesterol acyl-transferase (LCAT) activity. We also studied whether HDL lipid and protein compositions and LCAT activity were modified differently in growing rats during the consumption of two low-protein diets [2% casein (C) and 5% gluten (GI)] for 28 days, followed by the refeeding of a balanced diet containing 15% casein for 14 days. The control group was fed the balanced diet for 42 days. LCAT activity was determined by conversion of 3H-cholesterol into 3H-esterified cholesterol. The consumption of both protein-depleted diets highly decreased LCAT activity. At the end of the period of protein malnutrition, LCAT activity was only 22% and 13% of that of the control group in the C and GI groups, respectively. There was no significant difference between the two depleted diets. At day 3 of refeeding, values of both C and GI groups returned to control values. Despite the reduction in LCAT activity with both types of protein-depleted diets, HDL metabolism was not significantly impaired. This might be partly due to the maintenance of higher apolipoprotein A-I levels. The reduced LCAT activity could be attributable to reduced synthesis of LCAT in the liver during both protein-depleted diets.
Lamri
M Y
MY
Laboratoire de Physiologie Animale et de la Nutrition, Université d'Oran, Algeria.
Meghelli-Bouchenak
M
M
Boualga
A
A
Belleville
J
J
Prost
J
J
D000818:Animals; D016632:Apolipoprotein A-I / Q000378:metabolism; D002784:Cholesterol / Q000378:metabolism; D002788:Cholesterol Esters / Q000378:metabolism; D004032:Diet; D004044:Dietary Proteins / Q000008:administration & dosage*; D007700:Kinetics; D008075:Lipoproteins, HDL / Q000097:blood*; D008297:Male; D007862:Phosphatidylcholine-Sterol O-Acyltransferase / Q000097:blood*; D011488:Protein Deficiency / Q000097:blood*; D051381:Rats; D017208:Rats, Wistar; D014316:Tritium
D016632:Apolipoprotein A-I; D002788:Cholesterol Esters; D004044:Dietary Proteins; D008075:Lipoproteins, HDL; D014316:Tritium; D002784:Cholesterol; D007862:Phosphatidylcholine-Sterol O-Acyltransferase