Lower ability to oxidize lipids in adult patients with growth hormone (GH) deficiency: reversal under GH treatment

Clin Endocrinol (Oxf). 2006 Oct;65(4):423-8. doi: 10.1111/j.1365-2265.2006.02578.x.

Abstract

Background: The aim of the study was to characterize lipid oxidation at exercise in adults with growth hormone deficiency (GHD) and to evaluate the effect of 6 and 12 months of GH replacement therapy on substrate carbohydrate (CHO) and lipid utilization at exercise.

Patients and measurements: Twenty-five patients with GHD and 40 matched controls participated in the study. Ten of the 25 GH-deficient patients were treated with recombinant GH for 12 months. Anthropometric measurements and exercise calorimetry were performed before and after treatment. Maximal fat oxidation and the crossover point [that is the percentage of the theoretical maximal power (Wmax th) where CHO become the predominant fuel used for oxidation] were determined.

Results and conclusion: The GH-deficient patients exhibited a highly significant shift in the balance of substrate oxidation during exercise, towards a decrease in fat oxidation, and a shift towards lower intensities of the crossover (52 +/- 5.5%vs. 72.6 +/- 6.6% of Wmax th, P < 0.03) and maximal fat oxidation (131.04 +/- 14 vs. 234.4 +/- 30.1 mg/min, P < 0.03) in the GHD and control groups, respectively. However, GH treatment at 6 and 12 months partially reversed this defect, resulting in an increase (+83%, P < 0.001) in the maximal ability to oxidize fat during exercise. These findings are consistent with the hypothesis that a lack of GH reduces the ability to oxidize lipids during exercise and that GH treatment restores this muscular metabolic property.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adenoma / metabolism
  • Adult
  • Analysis of Variance
  • Body Composition
  • Carbohydrate Metabolism
  • Case-Control Studies
  • Cross-Sectional Studies
  • Energy Metabolism
  • Exercise / physiology*
  • Exercise Test / methods
  • Female
  • Follow-Up Studies
  • Growth Hormone / deficiency*
  • Growth Hormone / metabolism
  • Human Growth Hormone / therapeutic use
  • Humans
  • Hypopituitarism / drug therapy
  • Hypopituitarism / metabolism*
  • Lipid Metabolism*
  • Male
  • Muscle, Skeletal / metabolism
  • Oxygen Consumption
  • Pituitary Neoplasms / metabolism
  • Time Factors

Substances

  • Human Growth Hormone
  • Growth Hormone