Morris D D, Divers T J, Whitlock R H
Am J Vet Res. 1984 Nov;45(11):2431-5.
Four consecutive 6-hour urine collections were obtained from 10 healthy adult horses given free access to a complete pelleted ration and water. Samples of blood were collected from the jugular vein at the start of the test period and then every 6 hours for 4 consecutive samples. Mean renal clearance of creatinine (CCr) varied significantly during the four, 6-hour collections, ranging from 1.474 in period II to 2.702 ml/min/kg of body weight during period III (P less than 0.05). The CCr in period III was significantly different from the 24-hour mean value of 1.877 ml/min/kg (P less than 0.05). The mean 6-hour clearances of potassium (CK), chloride (CCl), and calcium (CCa) also varied significantly during the 4 collections (P less than 0.05). The 24-hour mean CK and CCl were different from the mean during period III (P less than 0.05). There was significant correlation between mean 24-hour CCr and CK (P less than 0.01); CCr and CCl (P less than 0.05); CNa and CK (P less than 0.01); CNa and CCl (P less than 0.01); and CK and CCl (P less than 0.001). The 95% confidence interval for 6-hour mean values of fractional excretion of Na (FENa) was 0.032% to 0.522%; FEK was 23.345% to 48.074%; FECl was 0.588% to 1.861%; and FECa was -0.158% to 6.723%. Although FENa, FECl, and FECa were highly variable within and between individual horses, mean values for periods I to IV did not differ significantly over time or from 24-hour mean values. The FEK varied less throughout the 24-hour test period. Mean urine volume, urine concentrations of Cr and K, urine osmolality, urine-to-plasma osmolality, urine-to-plasma urea nitrogen, and plasma urea nitrogen varied significantly through time periods I to IV (P less than 0.05); however, means for time periods I to IV were not different from 24-hour means.
从10匹健康成年马中获取连续4次6小时的尿液收集样本，这些马可自由获取完整的颗粒饲料和水。在试验期开始时从颈静脉采集血样，然后每6小时采集一次，连续采集4个样本。在4次6小时的收集过程中，肌酐的平均肾清除率（CCr）有显著变化，范围从第二期的1.474到第三期的2.702毫升/分钟/千克体重（P小于0.05）。第三期的CCr与24小时平均值1.877毫升/分钟/千克有显著差异（P小于0.05）。在4次收集过程中，钾（CK）、氯（CCl）和钙（CCa）的平均6小时清除率也有显著变化（P小于0.05）。24小时平均CK和CCl与第三期的平均值不同（P小于0.05）。24小时平均CCr与CK之间存在显著相关性（P小于0.01）；CCr与CCl之间（P小于0.05）；CNa与CK之间（P小于0.01）；CNa与CCl之间（P小于0.01）；以及CK与CCl之间（P小于0.001）。钠分数排泄（FENa）6小时平均值的95%置信区间为0.032%至0.522%；FEK为23.345%至48.074%；FECl为0.588%至1.861%；FECa为-0.158%至6.723%。尽管FENa、FECl和FECa在个体马之间和个体马内部变化很大，但第一至第四期的平均值在不同时间或与24小时平均值之间没有显著差异。FEK在整个24小时试验期内变化较小。平均尿量、尿液中Cr和K的浓度、尿渗透压、尿与血浆渗透压、尿与血浆尿素氮以及血浆尿素氮在第一至第四期随时间有显著变化（P小于0.05）；然而，第一至第四期的平均值与24小时平均值没有差异。
