Effects of menopause and high-intensity training on insulin sensitivity and muscle metabolism

Menopause. 2018 Feb;25(2):165-175. doi: 10.1097/GME.0000000000000981.

Abstract

Objective: To investigate peripheral insulin sensitivity and skeletal muscle glucose metabolism in premenopausal and postmenopausal women, and evaluate whether exercise training benefits are maintained after menopause.

Methods: Sedentary, healthy, normal-weight, late premenopausal (n = 21), and early postmenopausal (n = 20) women were included in a 3-month high-intensity exercise training intervention. Body composition was assessed by magnetic resonance imaging and dual-energy x-ray absorptiometry, whole body glucose disposal rate (GDR) by hyperinsulinemic euglycemic clamp (40 mU/m/min), and femoral muscle glucose uptake by positron emission tomography/computed tomography, using the glucose analog fluorodeoxyglucose, expressed as estimated metabolic rate (eMR). Insulin signaling was investigated in muscle biopsies.

Results: Age difference between groups was 4.5 years, and no difference was observed in body composition. Training increased lean body mass (estimate [95% confidence interval] 0.5 [0.2-0.9] kg, P < 0.01) and thigh muscle mass (0.2 [-0.1 to 0.6] kg, P < 0.01), and decreased fat percentage (1.0 [0.5-1.5]%, P < 0.01) similarly in the two groups. The postmenopausal women had lower eMR in vastus lateralis muscle than the premenopausal women (-14.0 [-26.0 to -2.0] μmol/min/kg, P = 0.02), and tended to have lower eMR in femoral muscles (-11.2 [-22.7 to 0.4] μmol/min/kg, P = 0.06), and also GDR (-59.3 [-124.8 to 6.3] mg/min, P = 0.08), but increased similarly in both groups with training (eMR vastus lateralis muscle: 27.8 [19.6-36.0] μmol/min/kg, P < 0.01; eMR femoral muscle: 20.0 [13.1-26.7] μmol/min/kg, P < 0.01, respectively; GDR: 43.6 [10.4-76.9] mg/min, P = 0.01). Potential mechanisms underlying the training-induced increases in insulin sensitivity included increased expression of hexokinase (19.2 [5.0-24.7] AU, P = 0.02) and glycogen synthase (32.4 [15.0-49.8] AU, P < 0.01), and also increased insulin activation of Akt2 (20.6 [3.4-29.0], P = 0.03) and dephosphorylation of glycogen synthase (-41.8 [-82.9 to -0.7], P = 0.05).

Conclusions: Insulin sensitivity was reduced in early postmenopausal women. However, postmenopausal women increased peripheral insulin sensitivity, skeletal muscle insulin-stimulated glucose uptake, and skeletal muscle mass to the same extent as premenopausal women after 3 months of high-intensity exercise training.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Absorptiometry, Photon
  • Adiposity
  • Female
  • Glucose / metabolism*
  • Glycogen Synthase / metabolism
  • Hexokinase / metabolism
  • Humans
  • Insulin Resistance*
  • Magnetic Resonance Imaging
  • Menopause / physiology*
  • Middle Aged
  • Physical Conditioning, Human / methods
  • Physical Conditioning, Human / physiology*
  • Positron Emission Tomography Computed Tomography
  • Postmenopause
  • Premenopause
  • Proto-Oncogene Proteins c-akt / metabolism
  • Quadriceps Muscle / diagnostic imaging
  • Quadriceps Muscle / metabolism*

Substances

  • Glycogen Synthase
  • Hexokinase
  • AKT2 protein, human
  • Proto-Oncogene Proteins c-akt
  • Glucose