Shpun S, Katz U
Department of Biology, Technion-Israel Institute of Technology, Haifa.
J Comp Physiol B. 1995;164(8):646-52. doi: 10.1007/BF00389806.
Kidney function of the euryhaline toad Bufo viridis was studied in animals acclimated to tap water and solutions of NaCl (230 and 500 mosmol.kg-1 H2O) and urea (500 mmol.l-1) in steady-state conditions. An ureter was catheterized for continuous urine collection and blood was sampled from an iliac artery. A single injection of 3H-inulin served for estimation of glomerular filtration rate: this was in the range of 15-27 ml.kg-1.h-1 and did not differ significantly in any of the acclimation conditions. Urine flow, on the other hand, varied considerably and was highest in tap water (18.2 +/- 3.2 ml.kg-1.h-1; urine/plasma inulin ratio = 0.88), lower in 230 mosmol.kg-1 H2O NaCl solution (13.5 +/- 3.9 ml.kg-1.h-1; u/p inulin ratio = 1.73) and lowest in 500 mosmol.kg-1 H2O NaCl or urea acclimation solutions (5-7 ml.kg-1.h-1; u/p inulin = 3.7-4.2). Clearance of free water was high in the tap water group, lower in 230 mosmol.kg-1 H2O NaCl solution, and much lower in the hyperosmotic acclimation conditions. Clearances of both Na+ and Cl- were similar under our experimental conditions, but changed independently in accordance to the composition of the acclimation solution. Potassium clearance was similar in all acclimation conditions, and a constant plasma K+ concentration was maintained. Urea clearance was high in tap water and 500 mmol.l-1 urea acclimation groups and low in the NaCl acclimations.(ABSTRACT TRUNCATED AT 250 WORDS)
在稳态条件下，对适应自来水、氯化钠溶液（230和500 mosmol·kg⁻¹ H₂O）以及尿素溶液（500 mmol·L⁻¹）的广盐性蟾蜍绿蟾蜍的肾功能进行了研究。通过插入输尿管以持续收集尿液，并从髂动脉采集血液样本。单次注射³H-菊粉用于估算肾小球滤过率：其范围为15 - 27 ml·kg⁻¹·h⁻¹，在任何适应条件下均无显著差异。另一方面，尿流量变化很大，在自来水中最高（18.2 ± 3.2 ml·kg⁻¹·h⁻¹；尿/血浆菊粉比值 = 0.88），在230 mosmol·kg⁻¹ H₂O氯化钠溶液中较低（13.5 ± 3.9 ml·kg⁻¹·h⁻¹；尿/血浆菊粉比值 = 1.73），在500 mosmol·kg⁻¹ H₂O氯化钠或尿素适应溶液中最低（5 - 7 ml·kg⁻¹·h⁻¹；尿/血浆菊粉 = 3.7 - 4.2）。自来水组的自由水清除率较高，在230 mosmol·kg⁻¹ H₂O氯化钠溶液中较低，在高渗适应条件下更低。在我们的实验条件下，Na⁺和Cl⁻的清除率相似，但根据适应溶液的组成独立变化。钾清除率在所有适应条件下相似，并且维持恒定的血浆K⁺浓度。尿素清除率在自来水和500 mmol·L⁻¹尿素适应组中较高，在氯化钠适应组中较低。（摘要截取自250字）
