Department of Nutritional Sciences, The Pennsylvania State University, University Park, PA 16802, USA.
Physiol Behav. 2011 Oct 24;104(5):687-93. doi: 10.1016/j.physbeh.2011.07.017. Epub 2011 Jul 27.
The individual roles of estradiol (E) and progesterone (P) in the control of food intake and body weight in ovariectomized (OVX) rats were investigated. Six groups of OVX Sprague-Dawley rats (n=9/group) were assigned to one of three 4-day cyclic hormone treatments: two groups were treated with E benzoate; two groups were treated with P; two groups were treated with both (EP). All rats had continuous access to chow and water throughout this 4-week study. One group of rats within each hormone treatment condition was fed chow ad libitum, and the second was subjected to a binge schedule: chow ad libitum plus 1-h access to an optional fat source on Monday, Wednesday, and Friday. A seventh OVX group (n=8) received the oil vehicle and chow. This group was included to monitor body weight and to verify hormone efficacy. The main findings were: (1) relative to rats receiving only P, E alone or EP attenuated 24-h chow intake tonically and cyclically, i.e. intake on Day 4, which models estrus, was lower in E and EP than in P, and also was lower than intake on Day 2, which models diestrus. In contrast, (2) neither E nor EP detectably affected optional fat intake during the 1-h fat access period relative to rats receiving only P when data were collapsed across the entire study. However, (3) E and EP had large effects on fat intake relative to P during the 1-h fat access period at the start of the study, but not at the end, when bingeing was fully established. (4) E and EP led to lower and apparently normal levels of body weight compared to rats receiving only the oil vehicle or only P. These results indicate that (1) administration of E alone has similar effects as co-administration of E and P on feeding and body weight in rats bingeing on fat, (2) with or without P, the inhibitory effects of E on meal size are compromised when bingeing on fat, and (3) the effects of E on binge size change dynamically as bingeing develops.
研究了雌二醇（E）和孕酮（P）在控制去卵巢（OVX）大鼠摄食和体重中的个体作用。将六组 OVX 斯普拉格-道利大鼠（每组 9 只）分为三组 4 天循环激素治疗之一：两组用苯甲酸雌二醇治疗；两组用孕酮治疗；两组同时用（EP）治疗。在这项为期 4 周的研究中，所有大鼠均持续获得饲料和水。在每种激素治疗条件下，一组大鼠自由进食，另一组则进行暴饮暴食：自由进食加周一、周三和周五 1 小时可选脂肪源。第七组 OVX 大鼠（n=8）接受油载体和饲料。包括这一组是为了监测体重并验证激素的功效。主要发现如下：（1）与仅接受 P 的大鼠相比，E 单独或 EP 可减弱 24 小时的饲料摄入，即模仿发情期的第 4 天的摄入低于 P，也低于模仿动情后期的第 2 天的摄入。相比之下，（2）在整个研究中，将数据汇总后，E 或 EP 对可选脂肪摄入量在 1 小时脂肪摄入期间没有明显影响，而仅接受 P 的大鼠则没有。然而，（3）E 和 EP 在研究开始时对 1 小时脂肪摄入期间的脂肪摄入相对于 P 有较大影响，但在完全建立暴饮暴食时，在研究结束时则没有。（4）与仅接受油载体或仅接受 P 的大鼠相比，E 和 EP 导致体重降低且明显正常。这些结果表明：（1）单独给予 E 的效果与同时给予 E 和 P 的效果相似，可抑制大鼠在脂肪暴食时的进食和体重增加；（2）无论是否存在 P，E 对餐量的抑制作用在暴食脂肪时会受到影响；（3）E 对暴食量的影响随着暴食的发展而动态变化。
