title: Insulin effects on protein synthesis are independent of glucose and energy metabolism.
abstract: Protein synthesis was accelerated in rat hearts that were provided insulin compared with provision of glucose or pyruvate alone or a mixture of glucose and pyruvate. The faster synthetic rates were accompanied by a reduction in numbers of ribosomal subunits, indicating that peptide chain initiation was accelerated relative to elongation/termination. In hearts supplied glucose, 65% of the maximal effect on protein synthesis was achieved by addition of 1.7 X 10(-10) M insulin, but significant effects on glucose uptake as well as on tissue contents of glucose 6-phosphate and creatine phosphate were obtained only with 7 X 10(-10) M insulin. Addition of glucose to perfusates containing pyruvate did not accelerate protein synthesis, although the glucose 6-phosphate content was raised. Similarly, the stimulatory effects of insulin on protein synthesis in hearts supplied pyruvate did not depend on changes in glucose 6-phosphate content, creatine phosphate/creatine, ATP/ADP, or adenylate energy charge. These studies indicate that insulin accelerated peptide-chain initiation and protein synthesis in rat heart by mechanisms independent of the hormone's effect on glucose or energy metabolism.
mesh_terms: D000227:Adenine Nucleotides / Q000378:metabolism; D000818:Animals; D004734:Energy Metabolism / Q000187:drug effects*; D005947:Glucose / Q000378:metabolism*; D006321:Heart / Q000187:drug effects; D007328:Insulin / Q000494:pharmacology*; D007700:Kinetics; D009682:Magnetic Resonance Spectroscopy; D008297:Male; D009206:Myocardium / Q000378:metabolism*; D010477:Perfusion; D010649:Phenylalanine / Q000378:metabolism; D014176:Protein Biosynthesis; D011773:Pyruvates / Q000378:metabolism; D019289:Pyruvic Acid; D051381:Rats; D011919:Rats, Inbred Strains
chemical_list: D000227:Adenine Nucleotides; D007328:Insulin; D011773:Pyruvates; D010649:Phenylalanine; D019289:Pyruvic Acid; D005947:Glucose