[Food intake-suppressing action of incretin and anti-obesity therapy].

ABSTRACT

Suppressing food intake is the most well-known central nervous action of glucagon-like peptide-1 (GLP-1). Neurons expressing preproglucagon (PPG) in the nucleus tractus solitarius (NTS) are the only source of "central" GLP-1, and they project to the hypothalamus. Recently, properties of these PPG-neurons have been revealed using transgenic mice expressing fluorescent protein under control of the PPG promoter; whereas they are directly responsible to leptin but not to GLP-1, they can be the second-order neurons of vagal afferents. "Peripheral" GLP-1 released from intestinal L-cells may possess central nervous action through the vagal afferent fibers. The question remains whether food intake suppression due to "peripheral" GLP-1 depends on "central" one. The action is being applied to anti-obesity therapy.