Odle J, Glass E N, Czarnecki-Maulden G L, Baker D H
Department of Animal Sciences, University of Illinois, Urbana 61801.
Adv Exp Med Biol. 1992;315:55-62. doi: 10.1007/978-1-4615-3436-5_7.
Urinary taurine excretion increases markedly when excess taurine is consumed. Experiments were designed to characterize this response in an attempt to develop an assay system for taurine bioavailability in common cat foods using an adult cat model. Initial studies investigated the time course of changes in urinary taurine excretion in response to alterations in taurine intake. The rate of urinary taurine excretion decreased rapidly when cats were switched from a casein diet supplemented with 0.2% crystalline taurine to a diet containing no supplemental taurine, reaching steady-state in 2 d. In contrast, urinary taurine excretion by cats switched from low to high taurine did not plateau until 6 to 7 d. Subsequently, cats (n = 18) were fed a casein diet containing graded levels of crystalline taurine (0, 0.025, 0.05, 0.10, 0.15 or 0.20%). After a 7-d adjustment period, urinary taurine excretion was quantified over a 5-d collection period and also by cystocentesis, and blood taurine levels were measured on d 6. Plasma taurine increased linearly (r = 0.88) as taurine intake increased, while whole-blood taurine increased asymptotically, reaching 95% of maximum concentration at a taurine intake of 93 mu mole/(kg body weight.d). The rate of urinary taurine excretion increased only slightly as taurine intakes increased to 96 mu mol/(kg body weight.d), but increased markedly (15-fold) thereafter. The same pattern was observed whether urinary taurine excretion was expressed as mu mole/(kg body weight.d) from total urine collection or as mu mole/g creatinine from cystocentesis.(ABSTRACT TRUNCATED AT 250 WORDS)
当摄入过量牛磺酸时，尿中牛磺酸排泄量会显著增加。设计了实验来表征这种反应，试图开发一种使用成年猫模型测定常见猫粮中牛磺酸生物利用度的检测系统。初步研究调查了牛磺酸摄入量改变时尿中牛磺酸排泄变化的时间进程。当猫从补充0.2%结晶牛磺酸的酪蛋白饮食转换为不补充牛磺酸的饮食时，尿中牛磺酸排泄率迅速下降，2天内达到稳态。相比之下，从低牛磺酸饮食转换为高牛磺酸饮食的猫，其尿中牛磺酸排泄直到6至7天才达到平稳状态。随后，给18只猫喂食含不同梯度结晶牛磺酸（0、0.025、0.05、0.10、0.15或0.20%）的酪蛋白饮食。经过7天的调整期后，在5天的收集期内通过总尿液收集和膀胱穿刺术对尿中牛磺酸排泄进行定量，并在第6天测量血中牛磺酸水平。随着牛磺酸摄入量增加，血浆牛磺酸呈线性增加（r = 0.88），而全血牛磺酸呈渐近性增加，在牛磺酸摄入量为93微摩尔/（千克体重·天）时达到最大浓度的95%。当牛磺酸摄入量增加到96微摩尔/（千克体重·天）时，尿中牛磺酸排泄率仅略有增加，但此后显著增加（15倍）。无论尿中牛磺酸排泄是以总尿液收集的微摩尔/（千克体重·天）表示，还是以膀胱穿刺术的微摩尔/克肌酐表示，都观察到相同的模式。（摘要截短于250字）
