Molecular Biology of Pituitary Tumours	
	
Genetic factors play a role in some pituitary tumours and, in familial multiple endocrine neoplasia type I (MEN I), prolactin-, GH-, and ACTH-secreting tumours contribute one of the neoplastic components. Recently, oncogenic mutations have been found in a subset of GH-producing adenomas, which are involved in their development.
GH-releasing hormone (GHRH) regulates pituitary somatotroph function by interacting with specific membrane receptors that activate adenylyl cyclase via the stimulating G protein, Gs. The consequent increase in intracellular cAMP levels stimulates GH secretion and somatotroph proliferation.