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.
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.
Brat
O
O
Endocrinology and Diabetes Research Unit, Sackler Faculty of Medicine, Tel Aviv University, Israel.
Ziv
I
I
Klinger
B
B
Avraham
M
M
Laron
Z
Z
D000293:Adolescent; D000328:Adult; D002648:Child; D002675:Child, Preschool; D015331:Cohort Studies; D005121:Extremities / Q000503:physiopathology; D005260:Female; D005500:Follow-Up Studies; D006130:Growth Disorders / Q000188:drug therapy* / Q000503:physiopathology; D019382:Human Growth Hormone / Q000008:administration & dosage / Q000172:deficiency* / Q000627:therapeutic use*; D006801:Humans; D007334:Insulin-Like Growth Factor I / Q000008:administration & dosage / Q000172:deficiency* / Q000627:therapeutic use*; D008297:Male; D008875:Middle Aged; D009119:Muscle Contraction / Q000187:drug effects / Q000502:physiology*; D010807:Physical Endurance / Q000187:drug effects / Q000502:physiology*
D019382:Human Growth Hormone; D007334:Insulin-Like Growth Factor I