Borghi C, Boschi S, Costa F V, Ambrosioni E
Department of Clinical Pharmacology and Therapeutics, University of Bologna, Italy.
Am J Hypertens. 1991 Jul;4(7 Pt 1):618-22. doi: 10.1093/ajh/4.7.618.
To evaluate the existence of a relationship between atrial natriuretic factor (ANF) and plasma Na+/K+ATPase inhibitory activity in humans, we examined the hemodynamic and humoral response to volume expansion in 41 borderline hypertensive patients (BHT) with either normal (n = 33) or low plasma renin activity (n = 8). The study was carried out by measuring blood pressure, forearm circulation, plasma renin activity (PRA), ANF, and plasma levels of an endogenous Na+/K+ATPase inhibitor before and after 2 h of acute intravenous NaCl infusion (0.22 mL/min/kg bodyweight). The early (45 min) changes of ANF and those of Na+/K+ATPase inhibitory activity attained at the end of saline infusion were inversely related in BHT with normal PRA and directly related in the low-PRA population (r = 0.64). The time-course of ANF response to sodium loading was significantly delayed in BHT characterized by normal venous distensibility. They also showed a greater increase in plasma Na+/K+ATPase inhibitory activity occurring with an hypertensive, vasoconstrictive, and sodium retaining response as well. We conclude that in normal PRA borderline hypertensives, ANF may modulate the release of a plasma Na+/K+ATPase inhibitor in a setting where extracellular volume is acutely expanded. Our findings also suggest that dissimilarities in peripheral venous distensibility are able to influence the time-course of ANF response. The blunted ANF increase observed in response to NaCl loading in a subset of BHT could represent an early marker of the attitude of such patients to develop high blood pressure leading to the release of a Na(+)-pump inhibitor and influencing individual salt-sensitivity.
为评估人类心房利钠因子（ANF）与血浆Na⁺/K⁺ATP酶抑制活性之间关系的存在情况，我们研究了41例临界高血压患者（BHT）在血容量扩张时的血流动力学和体液反应，这些患者血浆肾素活性正常（n = 33）或较低（n = 8）。通过在急性静脉输注NaCl（0.22 mL/分钟/千克体重）2小时前后测量血压、前臂循环、血浆肾素活性（PRA）、ANF以及内源性Na⁺/K⁺ATP酶抑制剂的血浆水平来进行本研究。在血浆肾素活性正常的BHT中，ANF的早期（45分钟）变化与盐水输注结束时达到的Na⁺/K⁺ATP酶抑制活性变化呈负相关，而在低血浆肾素活性人群中呈正相关（r = 0.64）。静脉扩张性正常的BHT对钠负荷的ANF反应时间进程明显延迟。他们还表现出血浆Na⁺/K⁺ATP酶抑制活性的更大增加，同时伴有高血压、血管收缩和钠潴留反应。我们得出结论，在血浆肾素活性正常的临界高血压患者中，在细胞外液急性扩张的情况下，ANF可能调节血浆Na⁺/K⁺ATP酶抑制剂的释放。我们的研究结果还表明，外周静脉扩张性的差异能够影响ANF反应的时间进程。在一部分BHT中观察到的对NaCl负荷的ANF反应迟钝可能代表这些患者发展为高血压并导致Na⁺泵抑制剂释放以及影响个体盐敏感性倾向的早期标志物。
