Influence of insulin on albumin and non-albumin protein fractional synthetic rates in post-absorptive type I diabetic patients.
Two 8-h primed continuous infusions of L-[1-13C] leucine were used to determine fractional synthesis rates of albumin and non-albumin plasma protein in post-absorptive Type I diabetic patients during insulin infusion and its withdrawal. Fractional protein synthetic rates were calculated from the rate of incorporation of 13C-label into protein and employing plasma 13C-alpha-ketoisocaproic acid enrichment to represent the precursor pools label. Incorporation of 13C into albumin and non-albumin plasma protein was linear over the latter 6 h of the 8-h L-[1-13C] leucine infusion. Fractional synthetic rates of plasma albumin and non-albumin proteins were similar during insulin withdrawal and its infusion. The increased whole-body protein synthesis observed during insulin withdrawal in Type I diabetic patients appears unrelated to events in albumin and non-albumin plasma protein fractions. These data are further evidence that insulin per se does not stimulate protein synthesis in man.
Nutrition Research Group, Clinical Research Centre, Harrow, Middlesex, UK.
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Pacy
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D000328:Adult; D000418:Albumins / Q000096:biosynthesis* / Q000302:isolation & purification; D001798:Blood Proteins / Q000096:biosynthesis* / Q000187:drug effects / Q000302:isolation & purification; D002247:Carbon Isotopes; D003922:Diabetes Mellitus, Type 1 / Q000097:blood* / Q000378:metabolism; D005260:Female; D006801:Humans; D007262:Infusions, Intravenous; D007328:Insulin / Q000008:administration & dosage / Q000494:pharmacology*; D007930:Leucine / Q000008:administration & dosage / Q000378:metabolism; D008297:Male; D008875:Middle Aged; D013268:Stimulation, Chemical
D000418:Albumins; D001798:Blood Proteins; D002247:Carbon Isotopes; D007328:Insulin; D007930:Leucine