Kaufman S
Department of Medicine, University of Alberta, Edmonton, Canada.
Can J Physiol Pharmacol. 1992 Aug;70(8):1104-8. doi: 10.1139/y92-153.
Atrial natriuretic factor (ANF) causes an increase in hematocrit that cannot be accounted for by urinary losses. The mechanism behind this phenomenon was studied in intact and splenectomized rats. Rat ANF 99-126 was infused i.v. for 30 min into conscious rats at rates of 0 (saline control), 0.05, or 0.1 microgram/min. Plasma volume was then determined by dilution of the dye, Evan's Blue. In one group of rats, red cell volume was determined using 51Cr-labelled erythrocytes. ANF infusion was continued uninterrupted throughout the experiments. In the intact rats, ANF (0.10 microgram/min) caused hematocrit to increase from 38.9 +/- 0.5 to 41.2 +/- 0.4% (p < 0.005). Splenectomy so attenuated this response to ANF that it failed to reach significance. Similarly, ANF (0.10 microgram/min) caused plasma volume to fall from 5.1 +/- 0.1 to 4.5 +/- 0.1 mL/100 g body wt. (p < 0.005) in the intact rats, but did not affect plasma volume in the splenectomized rats. As a result, blood volume was significantly reduced by ANF in the intact rats, but remained unchanged in the splenectomized rats. Red cell volume did not change in response to infusion of ANF, nor did ANF affect the rate of clearance of Evan's Blue out of the plasma. It is concluded that the spleen is an important site of movement of protein-poor fluid out of the vasculature, and that this exchange is influenced by ANF.
心房利钠因子（ANF）可使血细胞比容升高，这一升高无法用尿液流失来解释。在完整大鼠和脾切除大鼠中研究了这一现象背后的机制。将大鼠ANF 99 - 126以0（生理盐水对照）、0.05或0.1微克/分钟的速率静脉内输注到清醒大鼠体内30分钟。然后通过伊文思蓝染料稀释法测定血浆容量。在一组大鼠中，使用51Cr标记的红细胞测定红细胞容量。在整个实验过程中，ANF输注持续不间断。在完整大鼠中，ANF（0.10微克/分钟）使血细胞比容从38.9±0.5升高至41.2±0.4%（p<0.005）。脾切除术使对ANF的这一反应减弱，以至于未达到显著水平。同样，ANF（0.10微克/分钟）使完整大鼠的血浆容量从5.1±0.1降至4.5±0.1毫升/100克体重（p<0.005），但对脾切除大鼠的血浆容量没有影响。结果，ANF使完整大鼠的血容量显著降低，但脾切除大鼠的血容量保持不变。红细胞容量对ANF输注无反应，ANF也不影响伊文思蓝从血浆中的清除率。得出的结论是，脾脏是蛋白质含量低的液体从血管系统中移出的重要部位，并且这种交换受ANF影响。
