Luippold Gerd, Pech Bärbel, Schneider Swetlana, Osswald Hartmut, Mühlbauer Bernd
Department of Pharmacology, Faculty of Medicine, University of Tübingen, D-72074 Tübingen, Germany.
Am J Physiol Renal Physiol. 2002 May;282(5):F886-90. doi: 10.1152/ajprenal.00134.2001.
Renal function was studied in mice of different ages. In metabolic cage experiments, the renal electrolyte excretion was similar in young (n = 8; 5- to 7-wk-old) and adult (n = 6; 20- to 22-wk-old) CD-1 (ICR) BR mice, whereas spontaneous drinking volume and urinary flow rate were significantly higher in the adult compared with the young mice. Subsequently, the renal functional reserve was investigated by amino acid (AA) infusion (10%) in anesthetized young (n = 8) and adult (n = 6) mice. Because the body weight of adult mice was significantly higher than that of young animals, one group of adult mice (n = 8) received 12.5% AA to ensure that the dose of AA related to body weight was similar in both groups. Young animals constantly infused with Ringer solution served as time controls (n = 8). Glomerular filtration rate (GFR) at baseline was similar in each group. Because of AA, GFR significantly increased in young mice but not in both groups of adult animals, whereas in time controls GFR remained constant. Urinary flow rate and sodium excretion were elevated by AA in young and adult mice. We conclude that in CD-1 mice the first signs of age-related changes in kidney function concern alterations in renal hemodynamics, whereas renal tubular function appears to be preserved.
对不同年龄的小鼠进行了肾功能研究。在代谢笼实验中，年轻的（n = 8；5至7周龄）和成年的（n = 6；20至22周龄）CD-1（ICR）BR小鼠的肾脏电解质排泄情况相似，而成年小鼠的自发饮水量和尿流率显著高于年轻小鼠。随后，通过在麻醉的年轻（n = 8）和成年（n = 6）小鼠中输注氨基酸（AA）（10%）来研究肾脏功能储备。由于成年小鼠的体重显著高于年轻动物，一组成年小鼠（n = 8）接受12.5%的AA以确保两组中与体重相关的AA剂量相似。持续输注林格溶液的年轻动物作为时间对照（n = 8）。每组的基线肾小球滤过率（GFR）相似。由于输注AA，年轻小鼠的GFR显著增加，但两组成年动物的GFR均未增加，而在时间对照中GFR保持不变。AA使年轻和成年小鼠的尿流率和钠排泄增加。我们得出结论，在CD-1小鼠中，与年龄相关的肾功能变化的最初迹象涉及肾脏血流动力学的改变，而肾小管功能似乎得以保留。
