TRH and malnutrition: This axis controls energy homeostasis and expenditure; for example, fasting, malnutrition, or weight loss induce an axis adaptation leading to a reduced TRH expression in the PVN, which decelerates the HPT axis function and declines the fuel degradation rate, allowing animals to cope with their low nutrient availability (Blake et al., 1991; Van Haasteren et al., 1995).