Immunoreactive somatomedin B in acromegaly and in Turner's syndrome

Serum somatomedin B was measured by radioimmunoassay in forty-seven normal subjects, twenty-nine patients with acromegaly before and twenty-four after treatment, and eighteen patients with Turner's syndrome. Somatomedin B levels were significantly elevated in untreated acromegaly and in Turner's syndrome compared with the control group; they decreased following treatment of acromegaly. Because of the overlap between the groups, little information could be obtained from single somatomedin B estimations, which could, therefore, not replace dynamic tests of growth hormone secretion. No correlation between growth hormone and somatomedin B in acromegaly was detected; however, somatomedin B appeared to be related to the insulin response during the oral glucose tolerance test. In Turner's syndrome, no relationship between somatomedin B and insulin production, urinary oestrogen excretion, growth hormone secretion, gonadotrophin levels, age or height was found. The reason for the raised somatomedin B levels in Turner's syndrome remains at present unknown.