Growth hormone secretion is impaired in amyotrophic lateral sclerosis

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.

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.

Patients and controls underwent a GHRH plus arginine test. IGF-I was determined at baseline. A complete evaluation of pituitary function was also performed.

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.

The present data indicate a reduction of GH secretion in ALS patients.