Ise T, Kobayashi K, Biller W, Häberle D A
First Department of Internal Medicine, Faculty of Medicine, Kanazawa University, Japan.
Kidney Int Suppl. 1998 Sep;67:S245-9. doi: 10.1046/j.1523-1755.1998.06762.x.
The possible role of extracellular volume (ECV) expansion in prandial/postprandial natriuresis was evaluated in control, sham-operated (SO), and uninephrectomized (UNX) male Wistar rats fed a 0.64 (normal salt, NS) or 8 (high salt, HS) g% NaCl diet for seven days after UNX. We thus determined daily NaCl, diet, and water intake and Evans blue and inulin spaces on day 7. Finally, we determined Na and water clearance after a single i.g. Na load (581 micromol/100 g body weight) under chloralose/ketamine anesthesia in UNX and control HS rats. NaCl, diet, and water intakes were comparable beyond day 5. Plasma volume and ECV were similar in all groups. With NS diet, glomerular filtration rate (GFR) in UNX was compensated but lower than that of SO rats (0.55 vs. 0.74 ml/min per 100 g body weight). Blood pressure (BP) was 111 mm Hg in SO controls and 112 mm Hg in the UNX group. After oral Na loading, BP rose in both groups and remained higher in UNX (134 vs. 126 mm Hg at 15 minutes, 130 vs. 118 mm Hg at 225 minutes). Cumulative Na and water excretions were similar (513 and 610 micromol/100 g body weight, 1.97 and 2.35 ml/100 g body weight in SO and UNX, respectively). Chronically salt-loaded UNX rats seem to maintain dietary Na balance by mechanism(s) other than volume expansion.
在假手术（SO）对照组和单肾切除（UNX）的雄性Wistar大鼠中，评估细胞外液量（ECV）扩张在餐时/餐后利钠中的可能作用。这些大鼠在单肾切除术后，分别给予0.64（正常盐，NS）或8（高盐，HS）g%的NaCl饮食7天。因此，我们在第7天测定了每日NaCl、饮食和水的摄入量，以及伊文思蓝和菊粉空间。最后，我们在水合氯醛/氯胺酮麻醉下，对单肾切除和对照高盐大鼠进行单次口服钠负荷（581微摩尔/100克体重）后，测定了钠和水清除率。在第5天之后，NaCl、饮食和水的摄入量相当。所有组的血浆容量和ECV相似。给予NS饮食时，单肾切除大鼠的肾小球滤过率（GFR）得到代偿，但低于假手术大鼠（每100克体重0.55对0.74毫升/分钟）。假手术对照组的血压（BP）为111毫米汞柱，单肾切除组为112毫米汞柱。口服钠负荷后，两组血压均升高，单肾切除组仍较高（15分钟时为134对126毫米汞柱，225分钟时为130对118毫米汞柱）。累积钠和水排泄量相似（假手术组和单肾切除组分别为513和610微摩尔/100克体重，1.97和2.35毫升/100克体重）。长期盐负荷的单肾切除大鼠似乎通过容量扩张以外的机制维持饮食钠平衡。
