Hao J, Rabkin S W
University of British Columbia, Vancouver, Canada.
Can J Physiol Pharmacol. 1996 Jun;74(6):657-62.
The Dahl strain of genetically salt resistant (R) and salt sensitive (S) rats affords an opportunity to explore mechanisms for salt resistance and sensitivity. Because of the evidence that opioid peptides and their receptors can be involved in cardiovascular regulation, the objective of this study was to test the hypothesis that proopiomelanocortin (POMC), the precursor of beta-endorphin, is involved in the development of hypertension, through the determination of POMC mRNA in the pituitary. Three-week-old inbred Dahl R and S rats were maintained on a high salt diet (8% NaCl) or low salt diet (0.4% NaCl) for 6 weeks. POMC mRNA and for comparison preproenkephalin A (preproENK) mRNA were examined from tissues of Dahl R and S rats as determined by Northern blot analysis using beta-actin as an internal standard. POMC mRNA was abundant in the pituitary tissues. There was more POMC mRNA in the pituitary tissue of R rats compared with that of S rats on the high salt diet. Differences in POMC mRNA in the pituitary were not observed between R and S on the low salt diet. There were no differences in the levels of preproENK mRNA in the pituitary tissues of R and S rats on high or low salt diet. From these data, we propose that inefficient production of POMC mRNA is a characteristic of the Dahl S rat on a high salt diet.
具有遗传性抗盐（R）和盐敏感（S）特性的达尔系大鼠为探索抗盐和盐敏感机制提供了一个机会。鉴于有证据表明阿片肽及其受体可能参与心血管调节，本研究的目的是通过测定垂体中阿黑皮素原（POMC）信使核糖核酸（mRNA）来检验以下假设：β-内啡肽的前体POMC参与高血压的发生发展。将三周龄的近交系达尔R和S大鼠分别给予高盐饮食（8%氯化钠）或低盐饮食（0.4%氯化钠），持续6周。使用β-肌动蛋白作为内参，通过Northern印迹分析，检测达尔R和S大鼠组织中的POMC mRNA，并与前脑啡肽原A（preproENK）mRNA进行比较。POMC mRNA在垂体组织中含量丰富。高盐饮食条件下，R大鼠垂体组织中的POMC mRNA比S大鼠的更多。低盐饮食条件下，R和S大鼠垂体中的POMC mRNA未观察到差异。高盐或低盐饮食条件下，R和S大鼠垂体组织中preproENK mRNA水平均无差异。基于这些数据，我们认为POMC mRNA产生效率低下是高盐饮食条件下达尔S大鼠的一个特征。
