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., M. Rosická, M. Kršek, Z. Jarkovská, J. Marek, V. Schreiber., and Obsahuje bibliografii
Ghrelin is a new endogenous ligand for the growth hormone secretagogue receptor. It activates the release of growth hormone from the pituitary and it also participates in the regulation of energy homeostasis. The aim of the study was to characterize changes in serum ghrelin levels in obese subjects and their relationship to the serum levels of leptin and soluble leptin receptor. Eight obese patients (6 women and 2 men) with body mass index (BMI) 40.313.4 kg.m-2 and eight healthy controls (5 women and 3 men) with BMI 22.7±1.3 kg.m-2 were examined. The ghrelin serum levels (165.0±58.1 vs. 343.37±81.96; p<0.001) and soluble leptin receptor serum levels (7.25±3.44 vs. 21.80±4.99; p<0.0001) were significantly lower in obese patients. The leptin serum levels (23.45±12.90 vs. 6.41±2.96; p<0.005) were significantly higher compared to the lean subject group. In both measured groups the levels of serum leptin significantly positively correlated with BMI. We proved a significantly lower serum ghrelin levels in the group of obese patients in comparison with the control group., M. Rosická, M. Kršek, M. Matoulek, Z. Jarkovská, J. Marek, V. Justová, Z. Lacinová., and Obsahuje bibliografii