Fig. 1.

Agrp and Npy expression undergoes cyclic changes during the estrous cycle and such changes coincide with cyclic changes in food intake. (A, B) Phase of estrous cycle, food intake and body weight were determined daily in 12-week-old female mice (n = 12). Food intake and body weight measurements were normalized to measurements obtained in M-D for each mouse. **, P < 0.01 comparing food intake in M-D and P–E. ***, P < 0.001 comparing body weight in D and E using Student's paired t test. (C) Female mice were killed at 4 PM in different phases of the estrous cycle, and hypothalamic gene expression of Pomc, Lepr, Npy, and Agrp was analyzed by semiquantitative real time RT-PCR. β-actin was used as internal control. *, P < 0.05. Npy expression in M-D and P-E and Agrp expression in D-P and P-E were compared. n = 7 (M-D), 13 (D-P), 7 (P-E) and 9 (E-M). D, diestrus; P, proestrus; E, estrus; M, metestrus.