In vivo effects of hyperinsulinemia on lipogenic enzymes and glucose transporter expression in rat liver and adipose tissues.
Chronic hyperinsulinemia with maintenance of euglycemia was imposed on normal rats for 4 days. In white adipose tissue, hyperinsulinemia resulted in a twofold increase in GLUT4 protein and mRNA and a sixfold to 15-fold increase in fatty acid synthase (FAS) and acetyl coenzyme A (CoA) carboxylase (ACC) activity, respectively. Lipogenic enzyme mRNA was also markedly increased (20- to 30-fold). This was specific for white adipose tissue and was not observed in brown adipose tissue. In the liver, hyperinsulinemia was accompanied by a threefold increase in glucokinase (GK) activity and mRNA and by a threefold to fivefold increase in lipogenic enzyme activities and mRNA. In agreement with the changes in lipogenic activities, lipogenesis was markedly increased in white adipose tissue and liver of hyperinsulinemic rats. The data strongly suggest that in the rat, insulin is a driving force leading to increased lipid synthesis in liver and white adipose tissue.
Assimacopoulos-Jeannet
F
F
Laboratoires de Recherches Métaboliques, Faculty of Medicine, University of Geneva, Switzerland.
Brichard
S
S
Rencurel
F
F
Cusin
I
I
Jeanrenaud
B
B
D000103:Acetyl-CoA Carboxylase / Q000032:analysis*; D000273:Adipose Tissue / Q000187:drug effects / Q000378:metabolism*; D000279:Administration, Cutaneous; D000818:Animals; D002462:Cell Membrane / Q000378:metabolism; D064429:Fatty Acid Synthases / Q000032:analysis*; D005260:Female; D005947:Glucose / Q000008:administration & dosage / Q000378:metabolism; D051275:Glucose Transporter Type 4; D007260:Infusion Pumps; D007328:Insulin / Q000008:administration & dosage / Q000378:metabolism*; D008099:Liver / Q000187:drug effects / Q000378:metabolism*; D009004:Monosaccharide Transport Proteins / Q000032:analysis*; D009124:Muscle Proteins; D012333:RNA, Messenger / Q000032:analysis; D051381:Rats; D011924:Rats, Zucker
D051275:Glucose Transporter Type 4; D007328:Insulin; D009004:Monosaccharide Transport Proteins; D009124:Muscle Proteins; D012333:RNA, Messenger; C495694:Slc2a4 protein, rat; D064429:Fatty Acid Synthases; D000103:Acetyl-CoA Carboxylase; D005947:Glucose