Protein-carbohydrate interaction effects on energy balance, FGF21, IGF-1, and hypothalamic gene expression in rats

International audience; Amino acids are involved in energy homeostasis, just as are carbohydrates and lipids. Therefore, mechanisms controlling protein intake should operate independently and in combination with systems controlling overall energy intake to coordinate appropriate metabolic and behavioural responses. The objective of this study was to quantify the respective roles of dietary protein and carbohydrate levels on energy balance, plasma FGF21 and IGF-1 concentrations, and hypothalamic neurotransmitters (POMC, NPY, AgRP and CART). In a simplified geometric framework, 7-week-old male Wistar rats were fed 12 diets containing 3 to 30% protein for 3 weeks, in which carbohydrates accounted for 30 to 75% of the carbohydrate and fat part of the diet. As a result of this study, most of the studied parameters (body composition, energy expenditure, plasma FGF21 and IGF-1 concentrations and Pomc/Agrp ratio) responded mainly to the protein content and to a lesser extent to the carbohydrate content in the diet.