Effect of Orlistat (Xenical) on plasma levels of ghrelin in rats with/without experimental nutritional model of obesity

Energy homeostasis is a complex phenomenon that involves numerous processes and peptides interactions that are integrated by the brain. The brain receives continuous information about stored energy and current and anticipated fluxes in critical organs. The brain in turn determines when and how much food will be consumed. Premeal hunger and meal initiation are stimulated by interactions between gut hormones and the hypothalamus. Ghrelin is an acylated peptide secreted by the X/A endocrine cells in the stomach fundus. Originally described as a growth hormone (GH) secretagogue, the putative role of ghrelin in energy homeostasis has more recently been identified. Circulating ghrelin concentrations increase preprandially and decrease postprandially, and infusion of ghrelin induces increased appetite and food intake both in humans and rodents [(1-3,) (5)]. Although circulating ghrelin concentrations are decreased in obese humans and may not play an etiological role in their obesity, the effect of ghrelin antagonists on food intake and body weight is an area of interest [4]. Orlistat (Xenical) is a well-known anti-obesity drug which reduces low density lipoprotein and cholesterol levels independent of reductions of body weight [(9, 10)]. There are no data in the literature about its possible effect on the ghrelin secretion by the stomach mucosa.