The central signaling pathways related to metabolism-regulating hormones of the gut-brain axis: a review.

Obesity is a widespread metabolic disorder linked to various conditions, including type 2 diabetes, hypertension, fatty liver disease, sleep apnea, and hyperuricemia. It significantly impacts quality of life and economic productivity. Traditional methods like diet and lifestyle changes often fail to produce substantial weight loss. Consequently, emerging treatments such as anti-obesity medications, bariatric surgery, and fecal microbiota transplantation are becoming more prominent. Recent research emphasizes the role of hormones that communicate with the hypothalamus through the gut-brain axis, affecting appetite, insulin secretion, and body weight via specific signaling pathways. This review explores the role of key gastrointestinal hormones (GLP-1, PYY, ghrelin, CCK, GIP, leptin, and bile acids) and their signaling pathways in metabolic regulation. The present research systematically evaluates the impact of bariatric surgery on appetite modulation and certain metabolic functions through key signaling pathways, including GLP-1R, GHS-R1a, and FXR/TGR5.