Diabète & Obésité

Serum, plasma

Collect a morning or early afternoon sample (in special cases: food-intake should be taken in consideration). Samples should be stored at 2-8°C. Long-term storage at -20°C for several years.

Ghrelinconcentrations were measured between 300 and 4000 pg/ml Most samples were measured between 600 and 1400 pg/ml.

Human

Ghrelin is a 3.5 kDa protein, consisting of 28 amino-acids, octanoylated at the serine residue three. The biological activity of the peptide hormone depends on the acidification of this serine residue. Ghrelin ismainly synthesized in the stomach, but also in the duodenum and heart-cells. Ghrelin stimulates many neurological processes and the secretion of hormones as HGH, ACTH, cortisol and prolactin. Ghrelin can also be shown in the Islets of Langerhans and influence the regulation of the
insulin-secretion. Ghrelin receptors are located in the hypothalamic nucleus arcuatus, a brainregion, which has a key function in the hor-mone regulation of food-intake. Several studies showed a circadian rhythm of the ghrelinsecretion, con-trolled by food-intake.The ghrelin-plasma-concentrations increase shortly before food-intake and decrease after the meal. Plasma ghrelinlevels are decreased in chronic obesity, but elevated in anorexia nervosa.
For the regulation of food-intake and fat utilisation, ghrelin has possibly an opposite effect to that of leptin. In patients with prima-ry billiary cirrhosis the serum-ghrelin concentration decreases parallellto increasing leptin-levels – ghrelin negatively effects the adipo-genesis.