Effects of the beta-adrenoceptor agonist isoprenaline on insulin-sensitivity in soleus muscle of the rat.
The interactions between a beta-adrenoceptor agonist (isoprenaline) and insulin on rates of hexose transport, glucose phosphorylation, glycogen synthesis and glycogenolysis were investigated in the incubated stripped soleus-muscle preparation of the rat. In the presence of 1 microM-isoprenaline, insulin was less effective in stimulating glucose phosphorylation and glycogen synthesis. The stimulation of glycogenolysis by isoprenaline was only slightly decreased even at high (10000 microunits/ml) concentrations of insulin. Insulin-stimulated phosphorylation of 2-deoxyglucose was decreased by isoprenaline. It is suggested that this decrease in the rate of glucose phosphorylation is caused by the observed elevated concentration of glucose 6-phosphate, which inhibits hexokinase activity. This conclusion is supported by the fact that isoprenaline had no effect on the stimulation of 3-O-methylglucose transport by insulin.
D019325:3-O-Methylglucose; D000818:Animals; D003847:Deoxyglucose / Q000378:metabolism; D005947:Glucose / Q000378:metabolism; D019298:Glucose-6-Phosphate; D005958:Glucosephosphates / Q000378:metabolism; D006003:Glycogen / Q000378:metabolism; D066298:In Vitro Techniques; D007328:Insulin / Q000494:pharmacology*; D007545:Isoproterenol / Q000494:pharmacology*; D007773:Lactates / Q000378:metabolism; D019344:Lactic Acid; D008297:Male; D008757:Methylglucosides / Q000378:metabolism; D009132:Muscles / Q000187:drug effects / Q000378:metabolism*; D010766:Phosphorylation; D051381:Rats; D011919:Rats, Inbred Strains
D005958:Glucosephosphates; D007328:Insulin; D007773:Lactates; D008757:Methylglucosides; D019325:3-O-Methylglucose; D019344:Lactic Acid; D019298:Glucose-6-Phosphate; D006003:Glycogen; D003847:Deoxyglucose; D005947:Glucose; D007545:Isoproterenol