Dolan L M, Dobrozsi D J
Division of Endocrinology, Children's Hospital Medical Center, Cincinnati, Ohio 45229.
Pediatr Res. 1987 Aug;22(2):115-7. doi: 10.1203/00006450-198708000-00001.
The presence of immunoreactive atrial natriuretic polypeptide (ANP) has been demonstrated in fetal atria early in gestation but further definition of fetal ANP has not been reported. To characterize the principal molecular forms of fetal ANP and to compare fetal ANP to that of the adult of the same species, we extracted the atria of pregnant adult and 20-day fetal rats, the hearts of 14-day fetuses, and intact 12-day fetuses in 1 M acetic acid. Tissue collected from littermates was pooled. We measured ANP by radioimmunoassay before and after gel filtration on Sephadex G-75 in each group. ANP concentrations (means +/- 1 SD) in ng/mg protein and ng/animal were 1296 +/- 505 and 7707 +/- 1877 in adult atria (n = 17), 174 +/- 44 and 62 +/- 13 in 20-day fetal atria (n = 7), and 33 +/- 5.3 and 3.7 +/- 0.9 in 14-day fetal hearts (n = 6), respectively. Acid extracts from intact 12-day fetuses did not dilute in parallel to the standard curve; therefore, concentrations of ANP for the 12-day fetuses are not reported. ANP concentration rose from the 20-day fetus to the adult (p less than 0.0001). The major species of ANP eluting from the Sephadex column had an apparent molecular weight of 16 K in all groups. We conclude: 1) ANP is present in the fetus shortly after the completion of organogenesis; 2) 16 K ANP is the principal intracardiac species in the fetus and the adult; and 3) the existence of ANP soon after cardiac development suggests a possible role for ANP in fetal blood pressure and sodium and water homeostasis.
免疫反应性心房利钠多肽（ANP）在妊娠早期的胎儿心房中就已被证实存在，但胎儿ANP的进一步特征尚未见报道。为了明确胎儿ANP的主要分子形式，并将胎儿ANP与同一物种的成年个体进行比较，我们用1M乙酸提取了成年怀孕大鼠和20日龄胎儿大鼠的心房、14日龄胎儿的心脏以及完整的12日龄胎儿。将同窝幼崽收集的组织合并。我们在每组经Sephadex G - 75凝胶过滤前后，通过放射免疫分析法测定ANP。成年心房（n = 17）中ANP浓度（平均值±1标准差），以ng/mg蛋白质计为1296±505，以ng/动物计为7707±1877；20日龄胎儿心房（n = 7）中分别为174±44和62±13；14日龄胎儿心脏（n = 6）中分别为33±5.3和3.7±0.9。完整12日龄胎儿的酸提取物与标准曲线不成平行稀释关系；因此，未报告12日龄胎儿的ANP浓度。ANP浓度从20日龄胎儿到成年个体呈上升趋势（p＜0.0001）。从Sephadex柱上洗脱的ANP主要种类在所有组中表观分子量均为16K。我们得出以下结论：1）器官发生完成后不久，胎儿体内就存在ANP；2）16K ANP是胎儿和成年个体心脏内的主要种类；3）心脏发育后不久ANP的存在表明ANP在胎儿血压以及钠和水平衡中可能发挥作用。
