Somatomedin A in human serum, determined by radioreceptor assay.

Somatomedin A was determined by radioreceptor assay in serum from patients with various disorders. The mean values of somatomedin A in serum from 20 adult subjects, 21 patients with acromegaly, and 17 patients with hypopituitary dwarfism were 1.08 +/- 0.08, 3.02 +/- 0.33 and 0.44 +/- 0.03 U/ml, respectively. In children below 2 years of age, low levels were found (mean 0.40 +/- 0.04 U/ml). Normal levels were found in patients with Turner's syndrome and primary hypothyroidism, increased levels in uraemic patients, and decreased levels in Laron dwarfs.