Abstract
Objectives:
This study examines the role of insulin and angiotensin II in high-density lipoprotein (HDL) metabolism by focusing on the regulation and function of scavenger receptor type-BI (SR-BI) in adipose tissue.
Methods and results:
Insulin or angiotensin II injection in wild-type mice induced a decrease in circulating HDL and it was associated with the translocation of SR-BI from intracellular sites to the plasma membrane of adipose tissue. Refeeding upregulated adipose HDL selective cholesteryl esters uptake and SR-BI proteins through transcriptional and posttranscriptional mechanisms. This occurred along with a decrease in serum HDL and an increase in adipose cholesterol content. Similar results were obtained with transgenic mice overexpressing locally angiotensinogen in adipose tissue. In adipose 3T3-L1 cell line, HDL induced lipogenesis by increasing liver X receptor binding activity. This mechanism was dependent of insulin and angiotensin II.
Conclusions:
Our results raise the possibility that adipose tissue SR-BI translocation might be a link between adipose tissue lipid storage and HDL clearance.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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3T3-L1 Cells
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ATP Binding Cassette Transporter 1
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ATP-Binding Cassette Transporters / genetics
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ATP-Binding Cassette Transporters / metabolism
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Adipocytes / drug effects
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Adipocytes / metabolism
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Adipose Tissue / cytology
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Adipose Tissue / drug effects
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Adipose Tissue / metabolism*
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Adiposity* / drug effects
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Adiposity* / genetics
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Angiotensin II / metabolism*
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Angiotensin II / pharmacology
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Angiotensinogen / genetics
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Angiotensinogen / metabolism
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Animals
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Cell Membrane / metabolism
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Cholesterol / analogs & derivatives
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Cholesterol / metabolism
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Cholesterol, HDL / blood
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Cholesterol, HDL / metabolism*
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DNA-Binding Proteins / metabolism
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Eating
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Epididymis / metabolism
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Homeostasis
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Insulin / metabolism*
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Insulin / pharmacology
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Lipogenesis* / drug effects
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Lipogenesis* / genetics
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Liver X Receptors
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Male
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Mice
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Mice, Transgenic
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Orphan Nuclear Receptors
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Protein Transport
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RNA, Messenger / metabolism
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Receptors, Cytoplasmic and Nuclear / metabolism
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Scavenger Receptors, Class B / genetics
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Scavenger Receptors, Class B / metabolism*
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Sterol Regulatory Element Binding Protein 1 / genetics
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Sterol Regulatory Element Binding Protein 1 / metabolism
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Time Factors
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Transcription, Genetic
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Triglycerides / metabolism
Substances
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ATP Binding Cassette Transporter 1
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ATP-Binding Cassette Transporters
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Cholesterol, HDL
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DNA-Binding Proteins
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Insulin
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Liver X Receptors
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Orphan Nuclear Receptors
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RNA, Messenger
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Receptors, Cytoplasmic and Nuclear
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Scarb1 protein, mouse
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Scavenger Receptors, Class B
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Srebf1 protein, mouse
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Sterol Regulatory Element Binding Protein 1
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Triglycerides
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Angiotensinogen
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Angiotensin II
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cholesteryl oleyl ether
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Cholesterol