Czaja J A, Butera P C, McCaffrey T A
Behav Neurosci. 1983 Apr;97(2):210-20. doi: 10.1037//0735-7044.97.2.210.
Six experiments examined the effects of estradiol on ingestive behaviors of guinea pigs. Estradiol treatment was found to reduce water intake independently of its actions on food intake and body weight. In the first experiment, minimum intake and body weight of intact female guinea pigs coincided with rupture of the vaginal membrane, the estimated time of ovulation. In a second experiment, injections of 3 micrograms of estradiol benzoate per day to ovariectomized females significantly depressed food intake, water intake, and body weight, compared with oil injections. The ratio of water intake per gram of food intake did not change significantly during the estrous cycle or following estradiol injections, results suggesting that the reduced drinking might be a consequence of the reduced feeding. However, reducing food rations to 30% below ad lib levels in Experiment 3 by itself had no significant effect on drinking. In Experiment 4, therefore, ovariectomized females were first placed on a food ration 30% below ad lib levels and then injected daily with either 3 micrograms of estradiol benzoate or oil. Compared with oil injections, these estradiol injections significantly reduced water intake, while food intake did not decline significantly. In these experiments, the reduction in food intake was therefore neither a sufficient nor a necessary condition for the estradiol-induced suppression of water intake. The last two experiments verified that estradiol has independent actions on feeding. The daily water ration was reduced to 30% below ad lib levels in Experiment 5, with no significant effect on food intake. In the sixth experiment, the water ration was first reduced to 30% below ad lib levels, and then the ovariectomized females were injected with either oil or 3 micrograms of estradiol benzoate per day. With this reduced water ration, the estradiol significantly suppressed food intake while producing only minimal and insignificant changes in water intake. These findings established that estradiol can independently influence water intake and food intake in the guinea pig and thereby indicate that estradiol operates through di different mechanisms to produce these two effects.
六项实验研究了雌二醇对豚鼠摄食行为的影响。结果发现，雌二醇处理可独立于其对食物摄入和体重的作用而减少水的摄入量。在第一个实验中，完整雌性豚鼠的最低摄入量和体重与阴道膜破裂时间（估计的排卵时间）相吻合。在第二个实验中，与注射油剂相比，每天给去卵巢雌性豚鼠注射3微克苯甲酸雌二醇会显著降低食物摄入量、水摄入量和体重。在发情周期或注射雌二醇后，每克食物摄入量的水摄入量之比没有显著变化，这表明饮水减少可能是进食减少的结果。然而，在实验3中，将食物定量减少到自由采食水平以下30%本身对饮水没有显著影响。因此，在实验4中，先将去卵巢雌性豚鼠置于低于自由采食水平30%的食物定量下，然后每天注射3微克苯甲酸雌二醇或油剂。与注射油剂相比，这些雌二醇注射显著减少了水的摄入量，而食物摄入量没有显著下降。因此，在这些实验中，食物摄入量的减少既不是雌二醇诱导水摄入量抑制的充分条件，也不是必要条件。最后两项实验证实，雌二醇对进食有独立作用。在实验5中，每日水定量减少到自由采食水平以下30%，对食物摄入量没有显著影响。在第六个实验中，先将水定量减少到自由采食水平以下30%，然后给去卵巢雌性豚鼠每天注射油剂或3微克苯甲酸雌二醇。在这种减少的水定量情况下，雌二醇显著抑制了食物摄入量，而对水摄入量仅产生微小且不显著的变化。这些发现表明，雌二醇可独立影响豚鼠的水摄入量和食物摄入量，从而表明雌二醇通过不同机制产生这两种作用。
