Nazarloo Hossein Pournajafi, Nishiyama Mitsuru, Tanaka Yasushi, Asaba Koichi, Hashimoto Kozo
Second Department of Internal Medicine, Kochi Medical School, Kohasu, Okoh-cho, Nankoku 783-8505, Japan.
Regul Pept. 2002 May 15;105(2):121-9. doi: 10.1016/s0167-0115(02)00006-x.
The present study was conducted to assess the effect of nutritional stress induced by food deprivation on expression of messenger ribonucleic acid (mRNA) for corticotropin-releasing hormone receptor type 2beta (CRH-R2beta) in the rat cardiovascular system in the presence or absence of changes in circulating corticosterone. Food deprivation for 96 h caused a robust increase in plasma corticosterone levels and a significant decrease in CRH-R2beta mRNA expression in the rat heart. Starvation for 48 and 96 h decreased CRH-R2beta mRNA expression in the atria, ventricle as well as aorta of sham-adrenalectomized (sham) rats. Surprisingly, clamping plasma glucocorticoids at low levels by adrenalectomy with corticosterone pellet replacement (ADX+B) did not completely prevent starvation-induced decreases of CRH-R2beta mRNA expression in the rat cardiovascular system. Urocortin (Ucn) mRNA expression was increased significantly by food deprivation in the heart of sham as well as ADX+B rats. We speculate that food deprivation may increase urocortin, which in turn down-regulates CRH-R2beta mRNA expression in cardiovascular system. These data indicate that food deprivation despite the presence or absence of changes in circulating corticosterone may have an inhibitory effect on CRH-R2beta mRNA expression in the rat cardiovascular system.
本研究旨在评估在循环皮质酮水平有无变化的情况下，食物剥夺诱导的营养应激对大鼠心血管系统中促肾上腺皮质激素释放激素受体2β（CRH-R2β）信使核糖核酸（mRNA）表达的影响。96小时的食物剥夺导致大鼠血浆皮质酮水平显著升高，心脏中CRH-R2β mRNA表达显著降低。48小时和96小时的饥饿使假手术肾上腺切除（假手术）大鼠的心房、心室以及主动脉中CRH-R2β mRNA表达降低。令人惊讶的是，通过肾上腺切除并植入皮质酮丸剂（ADX+B）将血浆糖皮质激素水平维持在低水平，并不能完全阻止饥饿诱导的大鼠心血管系统中CRH-R2β mRNA表达的降低。假手术大鼠以及ADX+B大鼠的心脏中，食物剥夺显著增加了尿皮质素（Ucn）mRNA表达。我们推测，食物剥夺可能会增加尿皮质素，进而下调心血管系统中CRH-R2β mRNA表达。这些数据表明，无论循环皮质酮水平有无变化，食物剥夺可能都会对大鼠心血管系统中CRH-R2β mRNA表达产生抑制作用。
