A vitamin A-deficient diet results in glycogen deficiencybecause of impaired gluconeogenesis, caused by low Pck1expression (44–46). Stimulation of gluconeogenesis is mediateddirectly by the vitamin A metabolite atRA through RAreceptor response elements in the key gluconeogenic gene Pck1(44, 45). Here we demonstrate reciprocal regulation by energystatus of Rdh mRNA and atRA concentrations via insulineffects on FoxO1. Fasting-induced coordinate induction ofboth Rdh and Pck1 by FoxO1 stimulates gluconeogenesis (Fig.8). In the fed state, insulin repression of FoxO1 suppresses gluconeogenesisvia repressing both Rdh and Pck1. Althoughserum factor(s) other than insulin control Rdh expression andmRNA stability, we focused on insulin because of its criticalrole in regulating gluconeogenesis (9, 47).