Liu F Y, Cogan M G
Department of Medicine, University of California, San Francisco 94143.
Am J Physiol. 1988 Sep;255(3 Pt 2):F434-7. doi: 10.1152/ajprenal.1988.255.3.F434.
Atrial natriuretic factor (ANF) can functionally overcome the effects of angiotensin II in several tissues. Since ANF and angiotensin II in physiological concentrations have opposite effects on renal sodium excretion, we evaluated whether functional antagonism of the two hormones occurs in the proximal convoluted tubule, as has been recently reported with use of the shrinking split-droplet technique. We used the more conventional technique of in vivo microperfusion to measure the response to systemic ANF (0.5 micrograms.kg-1.min-1) when the endogenous angiotensin II level and proximal transport were normal or when transport was first stimulated by systemic angiotensin II administration (20 ng.kg-1.min-1). In both cases, ANF did not significantly alter bicarbonate, chloride, or water transport in either the early or late proximal convoluted tubule. This inability by ANF to directly affect proximal transport is consonant with the known lack of high-affinity receptors and appropriate second messenger system for ANF in the proximal convoluted tubule.
心房利钠因子（ANF）在多种组织中可在功能上拮抗血管紧张素II的作用。由于生理浓度的ANF和血管紧张素II对肾钠排泄具有相反的作用，我们评估了这两种激素在近端曲管中是否发生功能拮抗，正如最近使用收缩微滴技术所报道的那样。我们采用更为传统的体内微灌注技术，在体内血管紧张素II水平和近端转运正常时，或在首先通过全身给予血管紧张素II（20 ng.kg-1.min-1）刺激转运后，测量对全身ANF（0.5微克.kg-1.min-1）的反应。在这两种情况下，ANF均未显著改变近端曲管早期或晚期的碳酸氢盐、氯离子或水的转运。ANF无法直接影响近端转运，这与近端曲管中已知缺乏ANF的高亲和力受体和适当的第二信使系统是一致的。
