Fig. 1.

Daily (23 h) food intake, shown as number of 20-mg pellets eaten, in wild-type (WT), mice with disruption of the melanocortin-3 receptor gene (MC3R−/−), mice with disruption of the melanocortin-4 receptor gene (MC4R−/−), and double knockout (DKO) mice exposed to increasing fixed unit prices (nose pokes) per pellet. Each datum is the average of 4 days at each price step and 8–12 mice per genotype. Left: intake is shown in absolute terms. Right: intake is expressed relative to percentage of their intake at the lowest cost (FUP2).