ABSTRACT
Growth hormone [GH secretion is governed by GH-releasing hormone(GHRH)], somatostatin, and presumably, a third factor, as yet to be discovered, the putative natural ligand of the GH-releasing peptide (GHRP) receptor. Each of these hypophysiotropic factors interacts with one or more specific receptors of the seven-transmembrane domain, G-protein-coupled type. The relative contributions of the three factors to GH production and to the generation of a pulsatile secretion pattern remains somewhat unclear because of the difficulty in isolating their influences in the intact organism. Disturbances in any of the three can theoretically affect GH secretion. In this chapter we report a new type of genetic GH-deficient dwarfism that illustrates the critical necessity for GHRH signaling in the elaboration of GH.
