Department of Psychology, University at Buffalo, State Unioversity of New York, Buffalo, NY 14260, USA.
Endocrinology. 2013 Jan;154(1):320-9. doi: 10.1210/en.2012-1858. Epub 2012 Nov 26.
Estradiol (E2) decreases food and water intake in a variety of species, including rats. Available evidence suggests that this is mediated by genomic mechanisms that are most often attributed to nuclear estrogen receptors. More recent studies indicate that membrane-associated estrogen receptors (mERs) also can influence gene expression through the activation of transcription factors, yet it is unclear whether mERs are involved in mediating the hypophagic and antidipsetic effects of E2. In the present experiments, we injected E2 or a membrane-impermeable form of E2 (E2-BSA) into the lateral cerebral ventricle of ovariectomized female rats and evaluated the effect on 23 h food and water intake. First, we found that higher doses of E2 were necessary to reduce water intake than were sufficient to reduce food intake. Analysis of drinking microstructure revealed that the decrease in water intake after E2 treatment was mediated by both a decrease in burst number and burst size. Next, the activation of mERs with E2-BSA decreased both overnight food and water intake and analysis of drinking microstructure indicated that the decreased water intake resulted from a decrease in burst number. Finally, E2-BSA did not condition a taste aversion, suggesting that the inhibitory effects on food and water intake were not secondary to malaise. Together these findings suggest that activation of mERs is sufficient to decrease food and water intake in female rats.
雌二醇（E2）可降低包括大鼠在内的多种物种的食物和水摄入量。现有证据表明，这是通过基因组机制介导的，这些机制通常归因于核雌激素受体。最近的研究表明，膜相关雌激素受体（mERs）也可以通过激活转录因子来影响基因表达，但尚不清楚 mERs 是否参与介导 E2 的食欲减退和抗口渴作用。在本实验中，我们将 E2 或 E2 的一种膜不可渗透形式（E2-BSA）注射到去卵巢雌性大鼠的侧脑室中，并评估其对 23 小时食物和水摄入量的影响。首先，我们发现，与减少食物摄入量相比，需要更高剂量的 E2 才能减少水摄入量。对饮水微观结构的分析表明，E2 处理后水摄入量的减少是由爆发次数和爆发大小的减少介导的。接下来，用 E2-BSA 激活 mERs 可减少整夜的食物和水摄入量，并且对饮水微观结构的分析表明，水摄入量的减少是由于爆发次数的减少所致。最后，E2-BSA 不会引起味觉厌恶，这表明对食物和水摄入量的抑制作用不是不适的次要原因。这些发现表明，mERs 的激活足以减少雌性大鼠的食物和水摄入量。
