4th Serono Symposia Workshop on Clinical Paediatric Endocrinology
Salamanca, Spain, September 2-5, 2000
Guest Editors: K. Albertsson-Wikland, Göteborg; J. Argente, Madrid; J.L. Chaussain, Paris; H. Frisch, Vienna; U.E. Heinrich, Heidelberg; M.O. Savage, London; L. Tatò, Verona

Paper

Hormonal Control of Growth Hormone Secretion
M. Pombo^a, C.M. Pombo^b, A. Garcia^b, E. Caminos^b, O. Gualillo^c, C.V. Alvarez^b, F.F. Casanueva^c, C. Dieguez^b

Departments of
^aPediatrics,
^bPhysiology and
^cMedicine, Faculty of Medicine, University of Santiago, Santiago de Compostela, Spain

Address of Corresponding Author

Horm Res 2001;55:11-16 (DOI: 10.1159/000063456)

  Key Words

• Growth hormone
• GHRH
• Ghrelin
• Leptin

  Abstract

Growth hormone secretion by the somatotroph cells depends upon the interaction between hypothalamic regulatory peptides, target gland hormones and a variety of growth factors acting in a paracrine or autocrine fashion. This review will be focused on recent data regarding the mechanism by which growth hormone-releasing hormone (GHRH) influences somatotroph cell function and the physiological role played by Ghrelin and leptin in the regulation of growth hormone (GH) secretion. It is well established that binding of GHRH to its receptor leads to activation of protein kinase A (PKA). More recently, it was found that GHRH can also activate mitogen-activated protein (MAP) kinase both in pituitary cells and in a cell line overexpressing the GHRH receptor. Whether somatotroph adenomas, either with or without a GS-alpha mutation, have alterations in some of the components of the activation of the MAP kinase pathway remains to be known. The recent isolation of Ghrelin, the endogenous ligand of the growth hormone secretagogue receptor, can be considered a landmark in the GH field, which opens up the possibility of gaining greater insight into our understanding of the mechanisms involved in the regulation of GH secretion and somatic growth. Indeed, preliminary evidences indicate that this peptide exerts a marked stimulatory effect on plasma GH levels in both rats and humans. Finally, it is well known that GH secretion is markedly influenced by nutritional status. Leptin has emerged as an important adipose tissue-generated signal that is involved in the regulation of GH secretion, thus providing an integrated regulatory system of growth and metabolism. Although the effects of leptin on GH secretion in humans remain to be clarified, indirect evidences indicate that it may play an inhibitory role.

Copyright © 2001 S. Karger AG, Basel

  Author Contacts

C. Dieguez
Faculty of Medicine, University of Santiago
P.O. Box 563, E-15700 Santiago de Compostela (Spain)
Fax +34 981 572121, E-Mail fscadigo@usc.es

  Article Information

Number of Print Pages : 6
Number of Figures : 3, Number of Tables : 0, Number of References : 30