title: Effect of hyperinsulinemia on whole body and skeletal muscle leucine carbon kinetics in humans.
abstract: Data documenting the isolated effect of systemic hyperinsulinemia on whole body and skeletal muscle leucine carbon kinetics in humans are limited. Using steady-state [14C]leucine kinetics, 10 normal volunteers were studied in the baseline postabsorptive state and then under euglycemic, hyperinsulinemic (71 +/- 5 microU/ml), and euleucinemic conditions. Systemic hyperinsulinemia resulted in a significant decrease in whole body and forearm leucine rate of appearance (Ra) by 17 and 37%, respectively, (P less than 0.0003, 0.03), without a significant change in the nonoxidized rate of disappearance for either (P = 0.23, 0.66). The baseline contribution of total body skeletal muscle (TBSM) leucine Ra and rate of disappearance (Rd) to whole body leucine Ra and Rd was 27 +/- 6 and 24 +/- 5%, respectively. During hyperinsulinemia TBSM Ra decreased by 34%, whereas whole body Ra decreased by 16%. We conclude that the primary effect of insulin in the whole body and skeletal muscle is to decrease leucine release from protein without a significant effect on leucine incorporation into protein. This antiproteolytic effect of insulin is more pronounced in skeletal muscle than in other tissues in the body.
authors.affiliation: Department of Surgery, Memorial Sloan-Kettering Cancer Center, New York, New York 10021.
authors.forename: M J
authors.initials: MJ
authors.lastname: Heslin
authors.forename: E
authors.initials: E
authors.lastname: Newman
authors.forename: R F
authors.initials: RF
authors.lastname: Wolf
authors.forename: P W
authors.initials: PW
authors.lastname: Pisters
authors.forename: M F
authors.initials: MF
authors.lastname: Brennan
mesh_terms: D000596:Amino Acids / Q000097:blood*; D001639:Bicarbonates / Q000378:metabolism; D002250:Carbon Radioisotopes; D005260:Female; D006801:Humans; D006946:Hyperinsulinism / Q000378:metabolism*; D007328:Insulin / Q000494:pharmacology*; D007700:Kinetics; D007930:Leucine / Q000097:blood / Q000378:metabolism*; D008297:Male; D008875:Middle Aged; D008954:Models, Biological; D009132:Muscles / Q000378:metabolism*; D011865:Radioisotope Dilution Technique; D012964:Sodium / Q000378:metabolism; D017693:Sodium Bicarbonate
chemical_list: D000596:Amino Acids; D001639:Bicarbonates; D002250:Carbon Radioisotopes; D007328:Insulin; D017693:Sodium Bicarbonate; D012964:Sodium; D007930:Leucine