Untersuchungen zum Einfluss von Ghrelin auf die Biologie der Fettzelle

Abstract

Ghrelin, a 28-amino acid peptide, is known as orexigenic hormone. It is secreted from the stomach into the systemic circulation. Central nervous system pathways play a prominent role in mediating ghrelins orexigenic effects. Circulating ghrelin levels increase before food intake or during fasting and decrease after food intake. Several studies have shown that ghrelin regulates metabolic homeostasis of adipose tissue via central mechanisms. Ghrelin has also been shown to have direct effects on adipose tissue. Using the human SGBS preadipocyte cell strain, which has the capacity for adipocyte differentiation in vitro, we tested ghrelin-mediated influences on human adipocyte biology. In our experiments, ghrelin stimulates the proliferation of preadipocytes, but has no effect on adipogenic differentiation. Ghrelin increases basal adipogenesis and inhibits insulin-stimulated adipogenesis. These effects on adipogenesis are mediated by a GSK-3/Akt pathway. Furthermore, ghrelin stimulates expression of the proinflammatory cytokines IL-6 and IL-8 and has no effect on the expression of adiponectin. These findings demonstrate the effect of ghrelin on the adipose mass, the metabolism and the endocrine function of human SGBS preadipocytes. Ghrelin may therefore play an important role in therapy for obesity.