Cirio A, Boivin R, Grancher D
Laboratoire de physiologie et pharmacodynamie, Ecole nationale vétérinaire de Lyon, Marcy l'Etoile, France.
Ann Rech Vet. 1990;21(1):23-32.
Determinations of renal plasma flow (RPF), glomerular filtration rate (GFR) and urine flow in sheep fed low protein diets have yielded controversial data. In the present experiment, 8 sheep were fed a regular diet and another 6 received a low protein ration. Water intake and urine output were measured over 10 days. RPF and GFR were determined on 2 consecutive days. The latter determinations were repeated on 5 anaesthetized animals (sodium thiopental) in each group. An important increase in water intake (58%) and urine output (98%) was observed in the sheep on the low protein diet. In these animals, blood urea averaged 0.1 g/l. Urine output was greater (with a lower osmolarity) when the blood urea level was the lowest. RPF and GFR were significantly lower in the sheep on the low protein diet (RPF: 13.5 versus 28.1 ml/min/kg in the control animals; GFR: 1.61 versus 4.01 ml/min/kg); no relationship could be established with the blood urea level. The only effect of the anaesthesia was a reduction in RPF, of the same magnitude in both groups of sheep (about 35%). In conclusion, when sheep are fed a low protein diet, the volume of plasma processed through the kidney is decreased. In the present experiment, the increased urine flow and the lowered urinary osmolarity indicate an impaired renal concentrating ability. Barbiturate anaesthesia does not affect this phenomenon.
对喂食低蛋白日粮的绵羊的肾血浆流量（RPF）、肾小球滤过率（GFR）和尿流量的测定得出了有争议的数据。在本实验中，8只绵羊喂食常规日粮，另外6只接受低蛋白日粮。在10天内测量水摄入量和尿量。连续两天测定RPF和GFR。每组对5只麻醉动物（硫喷妥钠）重复进行后一项测定。观察到喂食低蛋白日粮的绵羊水摄入量（58%）和尿量（98%）有显著增加。在这些动物中，血尿素平均为0.1 g/l。当血尿素水平最低时，尿量更大（渗透压更低）。喂食低蛋白日粮的绵羊的RPF和GFR显著更低（RPF：对照动物为28.1 ml/min/kg，低蛋白日粮组为13.5 ml/min/kg；GFR：对照动物为4.01 ml/min/kg，低蛋白日粮组为1.61 ml/min/kg）；与血尿素水平无相关性。麻醉的唯一作用是RPF降低，两组绵羊降低幅度相同（约35%）。总之，当绵羊喂食低蛋白日粮时，通过肾脏处理的血浆量减少。在本实验中，尿量增加和尿渗透压降低表明肾脏浓缩能力受损。巴比妥类麻醉不影响这一现象。
