title: Subcellular distribution and phosphorylation state of insulin receptors from insulin- and isoproterenol-treated rat adipose cells.
abstract: Rat adipose cells treated with insulin followed by isoproterenol exhibit a change in glucose transporter intrinsic activity (lowered maximal activity) and a decrease in insulin sensitivity (rightward shift of the concentration-response curve) when assayed for 3-O-methylglucose transport. To investigate the latter phenomenon, the distribution and phosphorylation state of insulin receptors was examined. Isoproterenol augmented the effect of insulin to reduce cell surface receptors by 20-30%. These receptors were recovered in microsomal fractions. Isoproterenol also markedly reduced insulin-stimulated [32P]phosphate incorporation into the plasma membrane receptor beta-subunit. These effects may account for the effect of isoproterenol to decrease the sensitivity of the glucose transport response to insulin.
authors.affiliation: Experimental Diabetes, Metabolism and Nutrition Section, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892.
authors.forename: T M
authors.initials: TM
authors.lastname: Weber
authors.forename: H G
authors.initials: HG
authors.lastname: Joost
authors.forename: M
authors.initials: M
authors.lastname: Kuroda
authors.forename: S W
authors.initials: SW
authors.lastname: Cushman
authors.forename: I A
authors.initials: IA
authors.lastname: Simpson
mesh_terms: D000273:Adipose Tissue / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D000818:Animals; D002478:Cells, Cultured; D005947:Glucose / Q000378:metabolism; D007328:Insulin / Q000494:pharmacology*; D007545:Isoproterenol / Q000494:pharmacology*; D010766:Phosphorylation; D051381:Rats; D011919:Rats, Inbred Strains; D011972:Receptor, Insulin / Q000187:drug effects* / Q000378:metabolism
chemical_list: D007328:Insulin; D011972:Receptor, Insulin; D005947:Glucose; D007545:Isoproterenol