Serum insulin-like growth factor-I levels in amyotrophic lateral sclerosis.

The serum concentrations of the myotrophic hormone insulin-like growth factor-I (IGF-I) in 23 patients with amyotrophic lateral sclerosis were not significantly different from those found in the sera of 13 control patients. There was no difference in binding of 125I-IGF-I by serum from patients with amyotrophic lateral sclerosis in comparison with that found in the controls. These results indicate that immunoreactive IGF-I concentrations are normal in patients with amyotrophic lateral sclerosis and that such patients do not have significant antibodies binding their endogenous IGF-I.