Peripheral 5-HT mediates GnIH-induced feeding behavior and energy metabolism disorder in chickens via the 5-HT2C receptor

Gonadotropin-inhibitory hormone (GnIH) plays a critical role of reproduction in vertebrate since its discovery. Recently, a regulatory role of GnIH in appetite and the energy metabolism has emerged, despite its precise physiological mechanisms remain unknown. Thus, the present study evaluated the effects of a single or long-term GnIH treatments (administered via intraperitoneal injection) on the food intake, weight and glucolipid metabolism of chickens, while investigated the possible neuroendocrinology factors and its mechanism that involved in GnIH-induced obesity and glucolipid metabolism disorder. Our results showed that the intraperitoneal administration of GnIH to chickens resulted in marked body mass increased, hyperlipidemia, hyperglycemia and glucose intolerance. Subsequently, the results of metabolomics and pharmacological inhibition of 5-HT2C receptor studies revealed that blocked 5-HT2C receptor reinforced the effects of GnIH on food intake, body weight and the levels of blood glucose and lipid, resulted in GnIH-induced hyperglycaemia, hyperlipidemia and hepatic lipid deposition even worse, suggesting that peripheral 5-HT via 5-HT2C receptor may act as a negative feedback regulator to interplay with GnIH and jointly homeostatic control of energy balance in chickens. Our present study provide evidence of the cross-talk between GnIH and 5-HT in food intake and energy metabolism at the in vivo pharmacological level and to propose a molecular basis for these interactions, suggesting that functional interaction between GnIH and 5-HT may open new avenues to understand the mechanism of neuroendocrine network involved in appetite and energy metabolism as well as provide a new therapeutic strategy to prevent obesity, diabetes and metabolic disorders.