Somatomedin.

Somatomedin is a peptide component of serum which has been postulated to mediate the action of growth hormone on skeletal tissue. Direct effects on cartilage include stimulation of the synthesis of mucopolysacharide, protein, and nucleic acids. Insulin-like effects on non-skeletal tissues and cells have been described, and a relationship to NSILA-S and MSA has been suggested. The liver may be an important source. Non-specificity of bioassays is a problem. Growth hormone deficiency, malnutrition, therapy with corticosteroids or estrogens, and a type of dwarfism characterized by high serum growth hormone are associated with decreased somatomedin. An unexplained phenomenon is the normal somatomedin with low or undetectable growth hormone in certain cases of craniopharyngioma or other tumors involving the hypothalamus. Somatomedin is increased in acromegaly.