Olesen O V, Thomsen K
Acta Pharmacol Toxicol (Copenh). 1985 Sep;57(3):171-5. doi: 10.1111/bcpt.1985.57.3.171.
Clearance determinations were carried out in three groups of rats: A high lithium group given food to which 70 mmol/kg of lithium were added for 4-6 weeks leading to a mean serum lithium concentration of 0.85 mmol/l, a low lithium group given food to which 15 mmol/kg of lithium were added for two days before the clearance period leading to a mean serum lithium concentration of 0.22 mmol/l, and a group given the same food without lithium. The sodium and potassium contents of the food were kept high in order to avoid lithium-induced development of negative sodium balance and excessive polyuria. The rats were housed in four rooms with 6-hour displaced 24-hour light-dark cycles. The results showed that high doses of lithium led to a significant increase of the lithium clearance and the urine flow. Small amounts of lithium influenced neither the clearance values nor the urine flow. All renal variables were increased by about 50-100% during the dark period. The serum lithium concentration was least influenced by the diurnal rhythm. It is concluded that serum lithium concentrations measured at any time of the day are fairly representative of the 24 hours. A lithium clearance measured during daytime is valid for this period only. Long-term lithium treatment leads to an increase of the renal lithium clearance but does not diminish the normal diurnal rhythm of the kidney function.
高锂组给予添加了70 mmol/kg锂的食物，持续4 - 6周，导致平均血清锂浓度为0.85 mmol/l；低锂组在清除期前两天给予添加了15 mmol/kg锂的食物，导致平均血清锂浓度为0.22 mmol/l；还有一组给予不含锂的相同食物。食物中的钠和钾含量保持较高水平，以避免锂诱导的负钠平衡发展和过度多尿。大鼠饲养在四个房间，光照 - 黑暗周期为24小时，有6小时的偏移。结果表明，高剂量锂导致锂清除率和尿流量显著增加。少量锂对清除率值和尿流量均无影响。在黑暗期，所有肾脏变量均增加约50 - 100%。血清锂浓度受昼夜节律的影响最小。得出的结论是，一天中任何时间测量的血清锂浓度都能相当好地代表24小时的情况。仅在白天测量的锂清除率在此期间是有效的。长期锂治疗会导致肾脏锂清除率增加，但不会削弱肾脏功能的正常昼夜节律。
