Geary N, Trace D, McEwen B, Smith G P
Department of Psychiatry, Cornell University Medical College, NY.
Physiol Behav. 1994 Aug;56(2):281-9. doi: 10.1016/0031-9384(94)90196-1.
The influence of cyclic ovarian hormone replacement therapy on the satiety effect of exogenous CCK-8 was determined to investigate the mechanism mediating the preestrous decrease in meal size in female rats. Once weekly, food-deprived ovariectomized rats were IP injected with 0.5-4 micrograms/kg CCK-8 and offered 0.4-0.8 M sucrose 52 h after the second of two daily SC injections of 2.5 or 10 micrograms estradiol benzoate or vehicle and 4 h after 500 mg progesterone or vehicle. In each of three tests, estradiol significantly increased CCK-8's inhibitory effect on sucrose intake. In contrast, progesterone alone or in combination with estradiol did not consistently influence the satiating potency of CCK-8. The interaction of estradiol and CCK-8 was clearest for the dose of 4 micrograms/kg CCK-8. The interaction occurred during diurnal tests and during dark-onset tests in which estradiol did not decrease baseline sucrose intake. These results demonstrate that a cyclic regimen of estradiol replacement in ovariectomized rats is sufficient to enhance the satiating effect of exogenous CCK-8 and that simultaneous progesterone treatment does not influence this effect. Potentiation of the satiating effect of CCK released from the small intestine by ingested food may be one of the mechanisms by which food intake decreases during the period of high estrogen concentration in the estrus cycle.
为了研究介导雌性大鼠发情前期进食量减少的机制，确定了周期性卵巢激素替代疗法对外源性CCK-8饱腹感效应的影响。每周一次，对食物剥夺的去卵巢大鼠腹腔注射0.5 - 4微克/千克CCK-8，并在每天皮下注射2.5或10微克苯甲酸雌二醇或溶剂两次后的第二次注射后52小时，以及注射500毫克孕酮或溶剂后4小时，提供0.4 - 0.8 M蔗糖。在三项测试中的每一项中，雌二醇均显著增强了CCK-8对蔗糖摄入的抑制作用。相比之下，单独使用孕酮或孕酮与雌二醇联合使用，对CCK-8的饱腹感效力并没有一致的影响。对于4微克/千克CCK-8的剂量，雌二醇与CCK-8之间的相互作用最为明显。这种相互作用发生在昼夜测试期间以及雌二醇未降低基线蔗糖摄入量的暗期开始测试期间。这些结果表明，去卵巢大鼠中雌二醇替代的周期性方案足以增强外源性CCK-8的饱腹感效应，并且同时进行孕酮治疗不会影响这种效应。摄入食物从小肠释放的CCK饱腹感效应的增强可能是发情周期中雌激素浓度高的时期食物摄入量减少的机制之一。
