CENTRAL IMPLANTS OF DILUTE ESTRADIOL ENHANCE THE SATIETY EFFECT OF CCK-8

The following studies evaluated whether direct placement of estradiol into different brain areas could increase the satiating potency of CCK in female rats. In Experiment 1, estradiol implants in the PVN, but n ot in the VMN or third ventricle, significantly enhanced the satiety a ctions of CCK (5.0 mu g/kg). In Experiment 2, a lower dose of CCK (0.5 mu g/kg) suppressed food intake in females with estradiol implants in the PVN but not in animals with implants in the VMN or preoptic area. In both experiments, estradiol implants in the PVN significantly lowe red food intake and body weight during the 2-day period of hormone tre atment. Implants in other areas had no significant effects on feeding or body weight. These data support the hypothesis that the satiety eff ect of CCK is enhanced by estradiol and suggest that the PVN is involv ed in the interaction between CCK and estradiol.