Fig. 12.

Sex differences in the satiating effect of endogenous CCK in rats, assessed with the CCK-1 receptor antagonist devazepide. A and B: intact female rats were maintained in cages permitting recording of spontaneous meal patterns and were undisturbed except for daily injections of vehicle (Veh) or 1 mg/kg devazepide (Dev) 1 h before dark onset on the day of diestrus 2 or estrus. Note that devazepide significantly increased meal size during estrus (*P < 0.05), but not during diestrus, and that devazepide did not alter nocturnal meal frequency. Further tests indicated that the effect of devazepide did not depend on the smaller control meal sizes during estrus than diestrus 2 (data not shown). Reprinted from Peptides, Endogenous cholecystokinin's satiating action increases during estrus in female rats, Lisa A. Eckel and Nori Geary, 20: 451–456, 1999; republished with permission from Elsevier; from Eckel and Geary (204). C: intakes of 0.8 M sucrose during minute 5–45 in chronically estradiol-treated and control, oil-treated ovariectomized rats that sham fed with open gastric cannulas, were acutely pretreated with devazepide (Dev) or saline and received intraduodenal infusions of 10% Intralipid (0.44 ml/min) or saline (SAL) from minute 5 to 15. Note that estradiol increased the eating-inhibitory effect of Intralipid (*P < 0.05) and that this was completely reversed by Dev (+P < 0.05). From Asarian and Geary (17). D: devazepide-induced increases in nocturnal food intake (means ± SE) in female rats that were injected with 1 mg/kg devazepide every second day, according to a random schedule, and were tested for vaginal opening (puberty) daily, starting at 22 days of age. Puberty occurred at 30 ± 1 day of age, and rats cycled regularly thereafter, as indicated by observation of vaginal estrus every 4th or 5th day. Data are shown as mean intakes prior to puberty and on days of estrus in each week after puberty (devazepide had no effects on other days; data not shown). Note that devazepide increased food intake only after puberty. (*Significantly different from saline on matched test days, P < 0.05; **P < 0.01) (455).