Arai H, Nakao K, Saito Y, Morii N, Sugawara A, Yamada T, Itoh H, Shiono S, Mukoyama M, Ohkubo H
Department of Medicine, Kyoto University School of Medicine, Japan.
Biochem Biophys Res Commun. 1987 Oct 14;148(1):239-45. doi: 10.1016/0006-291x(87)91101-6.
Tissue levels of atrial natriuretic polypeptide (ANP) messenger RNA (ANPmRNA) and ANP in the rat heart were measured simultaneously. In Wistar rats, ANPmRNA of the same size (approximately 0.95 kbp) was detected in all four chambers of the rat heart. The ANPmRNA level was the highest in the right atrium, and the left atrial level was slightly lower than the right atrial level. Ventricular levels were more than two orders of magnitude lower than atrial levels. Tissue ANP concentrations of four chambers were roughly parallel to ANPmRNA levels. In spontaneously hypertensive rats (SHR) with the elevated plasma ANP level, the ANPmRNA level in the left atrium was substantially increased. The left/right ratio of atrial ANPmRNA level in SHR (150%) was higher than that in control Wistar Kyoto rats (WKY) (90%). In contrast, the left/right ratio of atrial ANP concentration was decreased in SHR (44%) compared with that in WKY (84%). The ratio of ANP to ANPmRNA levels in the left atrium of SHR was about three times smaller than that in the right atrium of SHR, and those in bilateral atria of WKY. These results indicate that the biosynthesis and secretion of ANP from the left atrium is preferentially increased in SHR. Thus, simultaneous determination of ANPmRNA and ANP levels is a refined strategy of investigation for the biosynthesis, storage and secretion of ANP.
同时测定了大鼠心脏中的心钠素（ANP）信使核糖核酸（ANPmRNA）和ANP的组织水平。在Wistar大鼠中，在大鼠心脏的所有四个腔室中均检测到相同大小（约0.95千碱基对）的ANPmRNA。ANPmRNA水平在右心房最高，左心房水平略低于右心房水平。心室水平比心房水平低两个数量级以上。四个腔室的组织ANP浓度大致与ANPmRNA水平平行。在血浆ANP水平升高的自发性高血压大鼠（SHR）中，左心房中的ANPmRNA水平显著增加。SHR中心房ANPmRNA水平的左/右比率（150%）高于对照Wistar Kyoto大鼠（WKY）（90%）。相反，与WKY（84%）相比，SHR中心房ANP浓度的左/右比率降低（44%）。SHR左心房中ANP与ANPmRNA水平的比率约为SHR右心房以及WKY双侧心房的三分之一。这些结果表明，在SHR中，左心房ANP的生物合成和分泌优先增加。因此，同时测定ANPmRNA和ANP水平是研究ANP生物合成、储存和分泌的一种精细策略。
