Particulate membranes prepared from a variety of monkey and rat tissues were shown
to have specific binding sites for somatomedin A. Binding to talc on the other hand
showed no specificity, and the sensitivity was less. The membrane bound somatomedin
A was displaced by somatomedin A in concentrations between 0.01 and 5 U/ml. Of the
other hormones tested only insulin in high concentrations could interfere with the
binding of labeled somatomedin A to tissue membranes. Membranes prepared from a number
of rat and monkey tissues also contained binding sites for insulin. Somatomedin A
could interfere with the binding of labeled insulin. No binding was observed for somatomedin
B in the tissues studied.
Somatomedin - Insulin - Binding Sites
