Glucocorticoid hormone receptors in rat pancreas

Abstract

Although glucocorticoids influence pancreatic function, it has not been established whether they act directly at the level of the pancreas, or indirectly by causing metabolic changes in other target tissues. As a step in elucidating the actions of glucocorticoids on the pancreas, a search was conducted for glucocorticoid hormone receptors in this tissue. Uptake and binding studies indicated that there were glucocorticoid hormone receptors in the high-speed cytosolic extract of rat pancreas. These receptors appear to be similar to other rat glucocorticoid receptors: they bind glucocorticoids rapidly in a reversible manner at 0 degrees C, competitive binding analysis studies show that they have a preference for glucocorticoids and, like other receptors, bind the synthetic steroids triamcinolone acetonide and dexamethasone with a higher affinity than corticosterone. Scatchard analysis demonstrated that there are 1.37 . 10(-13) mol glucocorticoid-binding sites/mg cytosolic protein. This demonstration of a glucocorticoid hormone receptor in pancreatic cytosol suggests that some of the effects glucocorticoids exert on pancreatic function are a consequence of their direct actions on this target tissue.