Objective: ALS is the most common motor neurone disorder in human adults. Scanty data on endocrine abnormalities have been reported. The aim of the present study was to investigate the GH-IGF-I axis in ALS patients.
Patients: Twenty-two ALS patients (12 men, 10 women), mean age 61 years, and 25 normal age- and sex-matched subjects. No patient was under riluzole therapy.
Measurements: Patients and controls underwent a GHRH plus arginine test. IGF-I was determined at baseline. A complete evaluation of pituitary function was also performed.
Results: Mean (+/- SD) basal GH levels were significantly reduced compared with normal controls (0.2 +/- 0.3 vs 1.6 +/- 1.8 ng/ml, P < 0.01), as well as peak GH concentrations after GHRH + arginine administration (12.6 +/- 8.9 vs 39.9 +/- 18.7 ng/ml, P < 0.001). Six (27%) patients showed a normal GH response to stimulus; 7 (32%) patients displayed a moderate GH deficiency; in 9 (40%) patients GH response was markedly deficient. IGF-I levels were normal in the majority of patients (mean +/- SD: 143.6 +/- 63.8 ng/ml). No significant correlation was observed between peak GH concentrations and age, BMI, disease duration, severity or clinical form. A higher incidence of GH deficiency was observed in male compared to female patients (83%vs 60%), with a peak GH response in males significantly lower than in females (8.9 +/- 6.6 vs 17 +/- 9.6 ng/ml, P = 0.03). Eighteen patients repeated the test after 5 months and similar results were obtained.
Conclusions: The present data indicate a reduction of GH secretion in ALS patients.