Subcellular distribution and phosphorylation state of insulin receptors from insulin- and isoproterenol-treated rat adipose cells.
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.
Weber
T M
TM
Experimental Diabetes, Metabolism and Nutrition Section, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892.
Joost
H G
HG
Kuroda
M
M
Cushman
S W
SW
Simpson
I A
IA
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
D007328:Insulin; D011972:Receptor, Insulin; D005947:Glucose; D007545:Isoproterenol