Department of Investigative Medicine, Imperial Weight Centre, Imperial College London, London, United Kingdom.
Surg Obes Relat Dis. 2011 Jan-Feb;7(1):68-73. doi: 10.1016/j.soard.2010.03.286. Epub 2010 Apr 1.
It was the aim to investigate the influence of gastric bypass on renal sodium and water handling. The relationship between sodium and water absorption along the gastrointestinal tract and their renal excretion is poorly understood. Beneficial effects on blood pressure have been seen after bariatric surgery before significant weight loss has occurred.
Male Wistar rats (348 ± 19 g) underwent either gastric bypass (n = 14) or sham operation (n = 7) and were given a low-sodium diet with deionized water ad libitum. Before and after surgery, the rats received an oral sodium load (1.5 mmol/kg) as hyperosmolar saline (616 mM), and were then placed in individual metabolic cages so the urine volume, sodium content, and water intake for 8 hours could be recorded. The urine sodium concentration was also measured.
The rats that had undergone gastric bypass had a significantly lower body weight than the sham-operated controls throughout the follow-up period (346 ± 21 g versus 501.3 ± 8.0 g at day 60; P = .0004). An oral sodium load after gastric bypass led to an increase in water intake (.07 ± .01 mL/g versus .03 ± .01 mL/g; P = .023), urine output (.03 ± .01 mL/g versus .02 ± .002 mL/g; P = .027), and sodium excretion (65.99 ± 10.7 mol versus 31.71 ± 8.7 mol; P = .020). No change was seen in water intake, urine output, or sodium excretion after sham surgery.
Urine output, water intake, and sodium excretion are all increased after gastric bypass surgery in rats given an oral sodium load compared with sham-operated controls. More rapid excretion, and less retention, of a dietary sodium load could be a part of the mechanism underlying the beneficial effect of bariatric surgery on blood pressure.
本研究旨在探讨胃旁路手术对肾脏钠水代谢的影响。目前，人们对胃肠道内钠水吸收与肾脏排泄之间的关系知之甚少。尽管在显著减重之前，减重手术已经显示出对血压有益的影响。
雄性 Wistar 大鼠（348 ± 19 g）接受胃旁路手术（n = 14）或假手术（n = 7），并给予含去离子水的低钠饮食。手术前后，大鼠给予口服高渗盐水（616 mM）作为钠负荷（1.5 mmol/kg），然后将其放入单独的代谢笼中，记录 8 小时的尿量、尿钠含量和水摄入量。还测量了尿钠浓度。
在整个随访期间，接受胃旁路手术的大鼠体重明显低于假手术对照组（第 60 天 346 ± 21 g 与 501.3 ± 8.0 g；P =.0004）。胃旁路手术后给予口服钠负荷会导致水摄入量增加（0.07 ±.01 mL/g 与 0.03 ±.01 mL/g；P =.023）、尿量增加（0.03 ±.01 mL/g 与 0.02 ±.002 mL/g；P =.027）和钠排泄增加（65.99 ± 10.7 mol 与 31.71 ± 8.7 mol；P =.020）。假手术组的水摄入量、尿量或钠排泄无变化。
与假手术对照组相比，给予口服钠负荷后，胃旁路手术后大鼠的尿量、水摄入量和钠排泄均增加。饮食钠负荷的排泄更快、潴留更少，这可能是减重手术对血压有益影响的机制之一。
