title: The muscle protein synthetic response to carbohydrate and protein ingestion is not impaired in men with longstanding type 2 diabetes.
abstract: Protein ingestion stimulates muscle protein synthesis and improves net muscle protein balance. Insulin resistance has been suggested to result in a reduced muscle protein synthetic response to food intake. As such, we hypothesized that type 2 diabetes patients have a impaired muscle protein synthetic response to food ingestion. To test this hypothesis, 10 male type 2 diabetes patients using their normal oral glucose-lowering medication (68 +/- 2 y) and 10 matched, normoglycemic men (65 +/- 2 y) were randomly assigned to 2 crossover treatments in which whole body and muscle protein synthesis were measured following the consumption of either carbohydrate (CHO) or carbohydrate with a protein hydrolysate (CHO+PRO). Primed, continuous infusions with L-[ring-13C6]phenylalanine and L-[ring-2H2]tyrosine were applied and blood and muscle samples were collected to assess whole-body protein balance and mixed muscle protein fractional synthetic rate over a 6-h period. Whole-body phenylalanine and tyrosine flux were higher after the CHO+PRO treatment compared with the CHO treatment in the diabetes and control group (P < 0.01). Protein balance was negative following CHO but positive following CHO+PRO treatment in both groups. Muscle protein synthesis rates were higher in both groups following the CHO+PRO (0.086 +/- 0.014%/h) treatment than in the CHO treatment (0.040 +/- 0.003%/h; P < 0.01) with no difference between the diabetes patients and normoglycemic controls. We conclude that the muscle protein synthetic response to CHO or CHO+PRO ingestion is not substantially impaired in longstanding, type 2 diabetes patients treated with oral blood glucose-lowering medication.
authors.affiliation: Department of Human Biology, Nutrition and Toxicology Research Institute Maastricht, Maastricht University, 6200 MD Maastricht, The Netherlands. r.manders@hb.unimaas.nl
authors.forename: Ralph J
authors.initials: RJ
authors.lastname: Manders
authors.forename: René
authors.initials: R
authors.lastname: Koopman
authors.forename: Milou
authors.initials: M
authors.lastname: Beelen
authors.forename: Annemie P
authors.initials: AP
authors.lastname: Gijsen
authors.forename: Will K
authors.initials: WK
authors.lastname: Wodzig
authors.forename: Wim H
authors.initials: WH
authors.lastname: Saris
authors.forename: Luc J
authors.initials: LJ
authors.lastname: van Loon
mesh_terms: D000368:Aged; D000596:Amino Acids / Q000097:blood; D001786:Blood Glucose / Q000378:metabolism; D018592:Cross-Over Studies; D003924:Diabetes Mellitus, Type 2 / Q000378:metabolism*; D004032:Diet; D004040:Dietary Carbohydrates / Q000494:pharmacology*; D004044:Dietary Proteins / Q000494:pharmacology*; D019587:Dietary Supplements; D004734:Energy Metabolism; D005786:Gene Expression Regulation / Q000187:drug effects; D006801:Humans; D007328:Insulin / Q000097:blood; D008297:Male; D009124:Muscle Proteins / Q000096:biosynthesis* / Q000235:genetics; D018482:Muscle, Skeletal / Q000187:drug effects / Q000378:metabolism*
chemical_list: D000596:Amino Acids; D001786:Blood Glucose; D004040:Dietary Carbohydrates; D004044:Dietary Proteins; D007328:Insulin; D009124:Muscle Proteins