Protein synthesis by perfused hearts from normal and insulin-deficient rats. Effect of insulin in the presence of glucose and after depletion of glucose, glucose 6-phosphate and glycogen.
In the absence of glucose, insulin stimulated the incorporation of (14)C-labelled amino acids into protein by perfused rat hearts that had been previously substantially depleted of endogenous glucose, glucose 6-phosphate and glycogen by substrate-free perfusion. This stimulation was also demonstrated in hearts perfused with buffer containing 2-deoxy-d-glucose, an inhibitor of glucose utilization. It is concluded that insulin exerts an effect on protein synthesis independent of its action on glucose metabolism. Streptozotocin-induced diabetes was found to have no effect either on (14)C-labelled amino acid incorporation by the perfused heart or on the polyribosome profile and amino acid-incorporating activity of polyribosomes prepared from the non-perfused hearts of these insulin-deficient rats, which show marked abnormalities in glucose metabolism. Protein synthesis was not diminished in the perfused hearts from rats treated with anti-insulin antiserum. The significance of these findings is discussed in relation to the reported effects of insulin deficiency on protein synthesis in skeletal muscle.
D000818:Animals; D001786:Blood Glucose / Q000032:analysis; D002247:Carbon Isotopes; D002499:Centrifugation, Density Gradient; D003920:Diabetes Mellitus / Q000139:chemically induced / Q000378:metabolism*; D005947:Glucose / Q000378:metabolism* / Q000494:pharmacology; D005958:Glucosephosphates / Q000378:metabolism*; D006003:Glycogen / Q000378:metabolism*; D006168:Guinea Pigs / Q000276:immunology; D006321:Heart / Q000187:drug effects; D007106:Immune Sera; D007328:Insulin / Q000494:pharmacology*; D007330:Insulin Antibodies; D007700:Kinetics; D008297:Male; D009124:Muscle Proteins / Q000096:biosynthesis*; D009206:Myocardium / Q000166:cytology / Q000378:metabolism*; D010477:Perfusion; D011132:Polyribosomes / Q000378:metabolism; D051381:Rats; D013311:Streptozocin
D001786:Blood Glucose; D002247:Carbon Isotopes; D005958:Glucosephosphates; D007106:Immune Sera; D007328:Insulin; D007330:Insulin Antibodies; D009124:Muscle Proteins; D013311:Streptozocin; D006003:Glycogen; D005947:Glucose