Estimation of Somatomedin-C Levels in Normals and Patients with Pituitary Disease by Radioimmunoassay

A C T The development of a radioimmunoassay for somatomedin-C has for the first time made it possible to discriminate between serum concentrations of a single peptide or closely related group of peptides and the net somatomedin activity measured by less specific bioassay and radioreceptor techniques. Anti- bodies to human somatomedin-C were raised in rabbits using a somatomedin-C ovalbumin complex as the anti- gen. A variety of peptide hormones at concentrations up to 1 ,uM are not recognized by the antibody.