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MINIREVIEW
Ghrelin - a New Endogenous Growth Hormone
Secretagogue
M. ROSICKÁ, M. KRŠEK, Z.
JARKOVSKÁ, J. MAREK, V. SCHREIBER
Third Department of Medicine, First Faculty
of Medicine, Charles University, Prague, Czech Republic
Received September 24,
2001
Accepted February 1, 2002
Summary
Ghrelin is a new endogenous peptide, discovered in 1999 by
Kojima et al., as the result of a search for an endogenous
ligand for an orphan receptor of known structure and function.
Ghrelin is composed of 28 amino acids and is produced mostly by
cells of the stomach, hypothalamus, and hypophysis, but it has
also been detected in other tissues. Its discovery is related to
the development of a new hypothesis regarding the regulation of
growth hormone secretion. It is an antagonist of somatostatin.
Ghrelin activates the release of growth hormone from the
somatotrophic cells of the hypophysis. It participates in the
regulation of energy homeostasis, increases food intake,
decreases energy output and exerts a lipogenetic effect. Its
metabolic effects do not depend on the GH/IGF-I system, but are
mediated by the NPY/Y1 and AGRP receptor system. Ghrelin
influences the secretion and motility of the gastrointestinal
tract, especially the stomach. The presence of ghrelin and its
receptors has also been demonstrated in many other tissues. Its
function in these tissues has not yet been studied, thus
providing many possibilities for further research.
Key
words
Energy expenditure · Ghrelin · Growth hormone secretagogue ·
Leptin · Ob/Ob Mice
Reprint
requests
Martina Rosická M.D., 3rd Dept. of Internal Medicine, 1st
Faculty of Medicine, Charles University, U nemocnice 2, 128 08,
Prague 2, Czech Republic, e-mail:
rosi@email.cz
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