Increased incorporation of dietary plant sterols and cholesterol correlates with decreased expression of hepatic and intestinal Abcg5 and Abcg8 in diabetic BB rats.
The aim of this study was to determine the impact of dietary plant sterols and stanols on sterol incorporation and sterol-regulatory gene expression in insulin-treated diabetic rats and nondiabetic control rats. Diabetic BioBreeding (BB) and control BB rats were fed a control diet or a diet supplemented with plant sterols or plant stanols (5 g/kg diet) for 4 weeks. Expression of sterol-regulatory genes in the liver and intestine was assessed by real-time quantitative polymerase chain reaction. Diabetic rats demonstrated increased tissue accumulation of cholesterol and plant sterols and stanols compared to control rats. This increase in cholesterol and plant sterols and stanols was associated with a marked decrease in hepatic and intestinal Abcg5 (ATP-binding cassette transporter G5) and Abcg8 (ATP-binding cassette transporter G8) expressions in diabetic rats, as well as decreased mRNA levels of several other genes involved in sterol regulation. Plant sterol or plant stanol supplementation induced the accumulation of plant sterols and stanols in tissues in both rat strains, but induced a greater accumulation of plant sterols and stanols in diabetic rats than in control rats. Surprisingly, only dietary plant sterols decreased cholesterol levels in diabetic rats, whereas dietary plant stanols caused an increase in cholesterol levels in both diabetic and control rats. Therefore, lower expression levels of Abcg5/Abcg8 in diabetic rats may account for the increased accumulation of plant sterols and cholesterol in these rats.
Scoggan
Kylie A
KA
Banting Research Center, Ottawa, Ontario, Canada. kylie_scoggan@hc-sc.gc.ca
Gruber
Heidi
H
Chen
Qixuan
Q
Plouffe
Louise J
LJ
Lefebvre
Jaclyn M
JM
Wang
Bingtuan
B
Bertinato
Jesse
J
L'Abbé
Mary R
MR
Hayward
Stephen
S
Ratnayake
W M Nimal
WM
D000071018:ATP Binding Cassette Transporter, Subfamily G, Member 5; D000071019:ATP Binding Cassette Transporter, Subfamily G, Member 8; D018528:ATP-Binding Cassette Transporters / Q000096:biosynthesis*; D000818:Animals; D002791:Cholesterol, Dietary / Q000494:pharmacology*; D003922:Diabetes Mellitus, Type 1 / Q000378:metabolism*; D004041:Dietary Fats / Q000494:pharmacology*; D015870:Gene Expression / Q000187:drug effects; D007421:Intestine, Small / Q000187:drug effects / Q000378:metabolism*; D008074:Lipoproteins / Q000096:biosynthesis*; D008099:Liver / Q000187:drug effects / Q000378:metabolism*; D026901:Membrane Transport Proteins / Q000378:metabolism; D010840:Phytosterols / Q000494:pharmacology*; D016133:Polymerase Chain Reaction; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D011913:Rats, Inbred BB
D000071018:ATP Binding Cassette Transporter, Subfamily G, Member 5; D000071019:ATP Binding Cassette Transporter, Subfamily G, Member 8; D018528:ATP-Binding Cassette Transporters; C480692:Abcg5 protein, rat; C480693:Abcg8 protein, rat; D002791:Cholesterol, Dietary; D004041:Dietary Fats; D008074:Lipoproteins; D026901:Membrane Transport Proteins; C482444:NPC1L1 protein, rat; D010840:Phytosterols; D012333:RNA, Messenger