Skeletal muscle myosin heavy chain synthesis in type 1 diabetes

Diabetes. 1997 Aug;46(8):1336-40. doi: 10.2337/diab.46.8.1336.

Abstract

Although insulin's anticatabolic effect on protein metabolism in type 1 diabetes has been clearly shown to be related to the inhibition of protein breakdown, insulin's effect on muscle protein synthesis remains controversial. Cross-limb studies and measurements of synthesis rates of mixed muscle protein have yielded conflicting results. These measurements represent the mean synthesis of several muscle proteins and may miss changes in the synthesis rates of individual muscle proteins. We measured the fractional synthesis rates of myosin heavy chain (MHC), the principal muscle contractile protein, and mixed muscle protein (MMP) in six type 1 diabetic patients during insulin deprivation and insulin treatment. Comparisons were made with six healthy control subjects. Muscle biopsies were taken at 2 h and 8 h during a primed continuous infusion of L-[1-13C]leucine. MHC was purified by a preparative continuous elution gel electrophoresis, and fractional synthesis rates were calculated. We found that in type 1 diabetic subjects, the fractional synthesis rates of MHC and MMP during insulin treatment are similar to those of control subjects. Acute insulin deprivation did not affect either the synthesis rate or the ratio of MHC to MMP in type 1 diabetic subjects. In the postabsorptive state, acute insulin deprivation has no effect on MHC or MMP synthesis in type 1 diabetic patients.

Publication types

  • Comparative Study
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Adult
  • Amino Acids / blood
  • Amino Acids / drug effects
  • Biopsy
  • Caproates / analysis
  • Caproates / chemistry
  • Caproates / metabolism
  • Carbon Isotopes
  • Diabetes Mellitus, Type 1 / blood
  • Diabetes Mellitus, Type 1 / drug therapy
  • Diabetes Mellitus, Type 1 / metabolism*
  • Female
  • Humans
  • Hypoglycemic Agents / administration & dosage
  • Infusions, Intravenous
  • Insulin / administration & dosage
  • Insulin / deficiency
  • Insulin / therapeutic use
  • Leucine / analysis
  • Leucine / metabolism
  • Male
  • Muscle Proteins / biosynthesis
  • Muscle Proteins / drug effects
  • Muscle, Skeletal / drug effects
  • Muscle, Skeletal / metabolism*
  • Muscle, Skeletal / pathology
  • Myosin Heavy Chains / biosynthesis*
  • Myosin Heavy Chains / drug effects
  • Myosin Heavy Chains / isolation & purification
  • Time Factors

Substances

  • Amino Acids
  • Caproates
  • Carbon Isotopes
  • Hypoglycemic Agents
  • Insulin
  • Muscle Proteins
  • isocaproic acid
  • Myosin Heavy Chains
  • Leucine