Concentrations of Immunoreactive Thyrotropin-Releasing Hormone in Spinal Cord of Patients with Amyotrophic Lateral Sclerosis

Concentrations of immunoreactive thyrotropin-releasing hormone (ir-TRH) were measured by specific radioimmunoassay in the spinal cord of six patients with amyotrophic lateral sclerosis (ALS) and seven with non- neurological diseases. Ir-TRH concentrations were the highest in the anterior horn, compared with other areas of the spinal cord, both in nonneurological diseases and ALS. Ir-TRH concentrations in the anterior horn of ALS were significantly lower than in nonneurological diseases, but were the same in both groups in other parts of the spinal cord (e.g. posterior horn, frontal part, lateral and central part, posterior part). Ir-TRH concentrations in rat spinal cords were stable for up to seven hours when spinal cord was stored after death at 4°C or 22°C. An elution profile of methanol-extracted human spinal cord on Sephandex G-10 column was identical to that of synthetic TRH. The cell population in the anterior horn in ALS was decreased markedly. The findings suggest that TRH is present in the human spinal cord and its decreased concentrations in the anterior horn of ALS may be due to a decrease in the cell population.