Romano G J, Mobbs C V, Howells R D, Pfaff D W
Rockefeller University, New York, NY 10021.
Brain Res Mol Brain Res. 1989 Jan;5(1):51-8. doi: 10.1016/0169-328x(89)90017-x.
Estrogen has been shown to increase proenkephalin (PE) mRNA levels in neurons of the ventrolateral aspect of the ventromedial hypothalamic nucleus (VL-VM). In this series of experiments, we examined the temporal qualities of this induction by determining both the latency of the estrogen-induced elevation in PE mRNA levels and the rate at which the message levels decline following removal of estrogen. In addition we have examined the effects of progesterone on PE gene expression in the VL-VM of estrogen-primed rats. The latency of the estrogen-induced elevation in PE mRNA levels was found to be relatively short: PE mRNA levels were increased 2-fold within 1 h of estrogen replacement. Following estrogen removal the levels of PE mRNA declined rapidly. Progesterone treatment attenuated this decline, prolonging the estrogen-induced elevation of PE mRNA levels. These results suggest that estrogen rapidly increases PE mRNA levels through a mechanism that probably involves alterations in both the rate of appearance and the rate of degradation of the message. Together, the short latency of the estrogen-induced elevation and the rapid rate of decay following estrogen removal indicate that PE gene expression is highly sensitive to fluctuating estrogen levels. The effect of progesterone suggests that this enkephalinergic system may be regulated by both estrogen and progesterone during the estrous cycle.
雌激素已被证明可增加腹内侧下丘脑核腹外侧（VL - VM）神经元中前脑啡肽原（PE）的mRNA水平。在这一系列实验中，我们通过确定雌激素诱导的PE mRNA水平升高的潜伏期以及去除雌激素后信息水平下降的速率，来研究这种诱导的时间特性。此外，我们还研究了孕酮对雌激素预处理大鼠VL - VM中PE基因表达的影响。发现雌激素诱导的PE mRNA水平升高的潜伏期相对较短：在雌激素替代后1小时内，PE mRNA水平增加了2倍。去除雌激素后，PE mRNA水平迅速下降。孕酮处理减弱了这种下降，延长了雌激素诱导的PE mRNA水平升高。这些结果表明，雌激素通过一种可能涉及信息出现速率和降解速率改变的机制迅速增加PE mRNA水平。总之，雌激素诱导升高的潜伏期短以及去除雌激素后迅速衰减的速率表明，PE基因表达对波动的雌激素水平高度敏感。孕酮的作用表明，在发情周期中，这个脑啡肽能系统可能受到雌激素和孕酮的共同调节。
