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This Article Full Text Full Text (PDF) All Versions of this Article: 289/5/E762    most recent 00203.2005v1 Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in Web of Science Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Web of Science (4) Citing Articles via Google Scholar Google Scholar Articles by Alba, M. Articles by Salvatori, R. Search for Related Content PubMed PubMed Citation Articles by Alba, M. Articles by Salvatori, R.

Effects of long-term treatment with growth hormone-releasing peptide-2 in the GHRH knockout mouse

¹Department of Medicine, Division of Endocrinology, and the Ilyssa Center for Molecular and Cellular Endocrinology Johns Hopkins University School of Medicine, Baltimore Maryland; ²Division of Endocrinology and Metabolism, Department of Internal Medicine, Tulane University Medical Center, New Orleans, Louisiana; and ³National Hormone and Peptide Program Harbor-UCLA Medical Center, Torrance, California

Submitted 5 May 2005 ; accepted in final form 20 May 2005

Growth hormone (GH) secretagogues (GHS) stimulate GH secretion in vivo in humans and in animals. They act on the ghrelin receptor, expressed in both the hypothalamus and the pituitary. It is unknown whether GHSs act predominantly by increasing the release of hypothalamic GH-releasing hormone (GHRH) or by acting directly on the somatotroph cells. We studied whether a potent GHS could stimulate growth in the absence of endogenous GHRH. To this end, we used GHRH knockout (GHRH-KO) mice. These animals have proportionate dwarfism due to severe GH deficiency (GHD) and pituitary hypoplasia due to reduced somatotroph cell mass. We treated male GHRH-KO mice for 6 wk (from week 1 to week 7 of age) with GH-releasing peptide-2 (GHRP-2, 10 µg sc twice a day). Chronic treatment with GHRP-2 failed to stimulate somatotroph cell proliferation and GH secretion and to promote longitudinal growth. GHRP-2-treated mice showed an increase in total body weight compared with placebo-treated animals, due to worsening of the body composition alterations typical of GHD animals. These data demonstrate that GHRP-2 failed to reverse the severe GHD caused by lack of GHRH.

growth hormone-releasing hormone

This article has been cited by other articles:

				M. Alba, D. Fintini, A. Sagazio, B. Lawrence, J.-P. Castaigne, L. A. Frohman, and R. Salvatori Once-daily administration of CJC-1295, a long-acting growth hormone-releasing hormone (GHRH) analog, normalizes growth in the GHRH knockout mouse Am J Physiol Endocrinol Metab, December 1, 2006; 291(6): E1290 - E1294. [Abstract] [Full Text] [PDF]