Az inkretin hormonok szerepe az inzulin-homeosztázis és a szénhidrát-anyagcsere szabályozásában Irodalmi összefoglaló

Abstract

Summary In the present literature review, the authors discuss the central role of the gutdriven incretin hormones, namely GIP (glucose-dependent insulinotropic polypeptide) and GLP-1 (glucagon-like peptide 1), as members of the enteroinsular axis, with regard on the pancreatic insulin production. The GIP, produced by K cells of the small intestines after feed intake, stimulates the insulin secretion of β cells mostly by the mediation of cAMP as a second messenger. Further, GLP-1, released from L cells, being presented in both small and large intestines, increases insulin synthesis by affecting insulin gene expression, enhances pancreatic insulin exocytosis and stimulates proliferation as well as differentiation of β cells. In addition, glucagon production of α cells can be inhibited by GLP-1, while GIP is capable to increase pancreatic glucagon secretion. Concerning the incretin effects in further tissues, lipogenesis and proliferation of osteoblasts can be also stimulated by GIP, leading to enhanced lipid storage in adipose tissue and to faster bone formation of growing animals, respectively. The way of incretin action is partly differing in birds from that of mammals, increasing pancreatic insulin release more likely by influencing the somatostatin production of δ cells rather than by direct stimulation of β cells. However, their anorexigenic effect, similarly to mammalian species, was stated in chicken, as well. Based on the available literature data, the authors declare that special emphasis should be taken on the role of incretin hormones in the complex regulation of insulin secretion. Influencing incretin and insulin homeostasis by nutrition or certain drugs can be of special relevance in the treatment of diabetic patients, and, based on insulin’s anabolic action, in improving the growth performance of food-producing animals.