Muscle force and endurance in untreated and human growth hormone or insulin-like growth factor-I-treated patients with growth hormone deficiency or Laron syndrome

Horm Res. 1997;47(2):45-8. doi: 10.1159/000185429.


Muscle force and endurance of four muscle groups (biceps, triceps, hamstrings and quadriceps) were measured by a computerized device in three groups: (A) 4 boys with isolated growth hormone deficiencies (IGHD) examined before at 10 and 24 months of hGH treatment; (B) 5 children (2 F, 3 M) with Laron syndrome were examined 3.5-4 years after initiation of insulin-like growth factor-I (IGF-I) treatment, and (C) comprised 8 untreated adults (5 F, 3 M) with Laron syndrome. For each patient, 2 matched controls, by age, sex, physical activity and height below the 50th percentile, were examined. GH- or IGF-I-deficient patients before treatment revealed reduced muscle force and endurance. GH treatment (0.6 U/kg/week) restored muscle force and endurance, progressively, mainly in the boys with puberty. Three to 4 years of IGF-I treatment (150 micrograms/kg/day) in patients with Laron syndrome proved to have a weaker effect than GH in restoring muscle force. The difference in effectiveness between hGH and IGF-I in restoring muscle force may be due to either the more marked muscle underdevelopment in Laron syndrome patients than in patients with IGHD or a difference in action potential between the two hormones.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adolescent
  • Adult
  • Child
  • Child, Preschool
  • Cohort Studies
  • Extremities / physiopathology
  • Female
  • Follow-Up Studies
  • Growth Disorders / drug therapy*
  • Growth Disorders / physiopathology
  • Human Growth Hormone / administration & dosage
  • Human Growth Hormone / deficiency*
  • Human Growth Hormone / therapeutic use*
  • Humans
  • Insulin-Like Growth Factor I / administration & dosage
  • Insulin-Like Growth Factor I / deficiency*
  • Insulin-Like Growth Factor I / therapeutic use*
  • Male
  • Middle Aged
  • Muscle Contraction / drug effects
  • Muscle Contraction / physiology*
  • Physical Endurance / drug effects
  • Physical Endurance / physiology*


  • Human Growth Hormone
  • Insulin-Like Growth Factor I