Growth hormone-releasing hormone and pituitary development, hyperplasia and tumorigenesis.

Growth hormone-releasing hormone (GHRH) is essential for expansion of the somatotrope lineage during pituitary development, and excessive GHRH secretion and/or action results in unregulated somatotrope proliferation and neoplastic transformation. Our understanding of the molecular and morphological bases for these effects from both animal and clinical studies has greatly increased during the past decade. However, many features of the cellular pathways remain to be defined, including the interaction of other genes in the multistep process of somatotrope tumorigenesis.