Chevalier R L, Thornhill B, Gomez R A, Ragsdale N V, Peach M J, Carey R M
Department of Pediatrics, University of Virginia School of Medicine, Charlottesville 22908.
Pediatr Res. 1990 Apr;27(4 Pt 1):396-400. doi: 10.1203/00006450-199004000-00014.
After acute blood volume expansion (BVE) in the rat, diuresis and natriuresis are reported to be minimal in rats 20 to 30 d of age, but increase to mature levels by 40 d of age. To evaluate the role of atrial natriuretic peptide (ANP) and its renal action in BVE, anesthetized Sprague-Dawley rats were studied at 25 to 30 (group I) and 45 to 50 d of age (group II). Hematocrit, mean arterial pressure, glomerular filtration rate, urine flow rate, urine sodium excretion, urine cyclic GMP excretion, and plasma ANP concentration [( ANP]) were measured before and after infusion of donor littermate whole blood, 2.5% body wt (BVE), and in time controls (no BVE) in each group. Baseline hematocrit, mean arterial pressure, and glomerular filtration rate were greater in group II than group I, but urine flow rate, urine sodium excretion, urine cyclic GMP excretion, and [ANP] did not differ. BVE caused a prompt increase in urine flow rate, urine sodium excretion, and [ANP], but not urine cyclic GMP excretion, in both groups, but there was no difference in the response between groups. Additional groups of rats of the same ages as groups I and II studied using a protocol similar to that of a previous report also showed the "mature" diuretic and natriuretic response even in the younger animals. We conclude that there is no further maturation of the renal response to acute BVE in the euvolemic rat after 25 d of age. The increase in [ANP] after acute BVE in the immature weanling rat is consistent with a role for ANP in mediation of the renal response.
据报道，大鼠急性血容量扩张（BVE）后，20至30日龄大鼠的利尿和利钠作用最小，但到40日龄时增加到成熟水平。为了评估心房利钠肽（ANP）及其在BVE中的肾脏作用，对25至30日龄（I组）和45至50日龄（II组）的麻醉Sprague-Dawley大鼠进行了研究。在每组输注供体同窝全血（2.5%体重，BVE）前后以及时间对照组（无BVE）中，测量了血细胞比容、平均动脉压、肾小球滤过率、尿流率、尿钠排泄、尿环磷酸鸟苷排泄和血浆ANP浓度[（ANP）]。II组的基线血细胞比容、平均动脉压和肾小球滤过率高于I组，但尿流率、尿钠排泄、尿环磷酸鸟苷排泄和[ANP]无差异。BVE使两组的尿流率、尿钠排泄和[ANP]迅速增加，但尿环磷酸鸟苷排泄无变化，且两组之间的反应无差异。使用与先前报告类似的方案对与I组和II组年龄相同的额外几组大鼠进行研究，结果表明即使是较年轻的动物也有“成熟”的利尿和利钠反应。我们得出结论，25日龄后，正常血容量大鼠对急性BVE的肾脏反应不再进一步成熟。未成熟断奶大鼠急性BVE后[ANP]的增加与ANP在介导肾脏反应中的作用一致。
