In some GH-secreting adenomas, intracellular cAMP concentration and secretory activity are elevated, even under nonstimulated conditions. In these tumours, oncogenic mutation in the chain genes of the Gs has been shown. The resulting activation of adenylyl cyclase bypasses the normal requirement of the cell to be activated by GHRH and is thus autonomous. Such exciting studies suggest that we are beginning to understand the pathogenesis of pituitary tumours.
