Abstract
Using a highly sensitive radioimmunoassay (RIA), serum somatc-medin-C (Sm-C) concentrations were determined in a variety of clinical conditions. Relative to a pooled serum standard containing 1.0 u of Sm-C activity/ml, levels for normals were lowest in cord serum (0.38±0.05[SEM]u/ml), rose rapidly in early life, and approached adult levels (1.50±0.10u/ml) by 5 years of age. Evidence that the substance measured is growth hormone (hGH) dependent includes the finding that 14 acromegalics had a mean value of 6.28±0.37 u/ml, while 19 hypopituitary children all had levels below 0.2 u/ml. Serum Sm-C concentrations rose significantly in 9 of 10 hypopituitary patients within 12 hours following hGH administration. Four children with psychosocial dwarfism had low Sm-C levels prior to hospltalization and showed significant increases concurrent with accelerated linear growth. Concentrations were normal in 10 patients with achondroplasia (1.19±0.14u/ml) and 7 children with non-hGH deficient dwarfism (1.55±0.50u/ml). Six children with hypothyroidism had a mean level of 0.80±0.23u/ml. The mean serum Sm-C concentration in 4 patients with cortisol excess was elevated (2.6±0.10u/ml). Five patients with protein calorie malnutrition and elevated hGH had low Sm-C levels. In three, significant rises were observed during refeeding. Evidence was obtained that a portion of the activity detected in bioassays and membrane receptor assays is not attributable to Sm-C and is less hGH dependent.
Article PDF
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Furlanetto, R., D'ercole, A., Underwood, L. et al. EXPERIENCE WITH A NEW RADIOIMMUNOASSAY FOR SOMATOMEDIN-C. Pediatr Res 11, 426 (1977). https://doi.org/10.1203/00006450-197704000-00339
Issue Date:
DOI: https://doi.org/10.1203/00006450-197704000-00339