Shalmi M, Thomsen K
Department of Pharmacology, University of Copenhagen, Denmark.
Eur J Pharmacol. 1993 Jan 5;230(1):33-9. doi: 10.1016/0014-2999(93)90406-8.
We examined the effects of amiloride administration on the renal lithium clearance (CLi) in three series of conscious, unrestrained rats maintained on either a low (5 mmol/kg) or normal (200 mmol/kg) sodium diet. In series 1, six doses of amiloride (0.5-16 mg/kg) were administered s.c., and the renal electrolyte excretion was assessed over a 3-h clearance period. In series 2, the time profile of changes in renal electrolyte excretion following 4 mg/kg of amiloride s.c. was examined, and in series 3, the effect of amiloride infusion i.v. (1 mg/kg followed by 2 mg/kg per h) on renal function was investigated. In all series CLi was lower in sodium-restricted rats than in controls. Amiloride administered s.c. to sodium-restricted rats did not increase the 3-h CLi to the levels found in control rats. When amiloride was administered s.c. or i.v. and urine collected in 30-minute periods, CLi in rats fed a sodium-deficient diet increased to control levels. We conclude that amiloride-induced losses of sodium and water in CLi studies may lead to an erroneous interpretation of data. However, distal tubular lithium reabsorption may be recognized, if present, by the administration of amiloride i.v. or s.c. during collections of urine in short time intervals.
我们在三组清醒、未受限制的大鼠中研究了给予氨氯吡咪对肾锂清除率（CLi）的影响，这些大鼠分别维持低钠（5 mmol/kg）或正常钠（200 mmol/kg）饮食。在第一组中，皮下注射六剂氨氯吡咪（0.5 - 16 mg/kg），并在3小时的清除期内评估肾电解质排泄。在第二组中，研究了皮下注射4 mg/kg氨氯吡咪后肾电解质排泄变化的时间曲线，在第三组中，研究了静脉输注氨氯吡咪（1 mg/kg，随后每小时2 mg/kg）对肾功能的影响。在所有组中，钠限制大鼠的CLi均低于对照组。对钠限制大鼠皮下注射氨氯吡咪并未使3小时CLi增加到对照组大鼠的水平。当皮下或静脉注射氨氯吡咪并每隔30分钟收集尿液时，喂食缺钠饮食大鼠的CLi增加到对照水平。我们得出结论，在CLi研究中，氨氯吡咪引起的钠和水丢失可能导致对数据的错误解释。然而，如果存在远端肾小管锂重吸收，可通过在短时间间隔收集尿液期间静脉或皮下注射氨氯吡咪来识别。
