Yamamoto A, Yoshida K, Wada O
J Toxicol Sci. 1981 Nov;6(4):325-33. doi: 10.2131/jts.6.325.
In order to ascertain the origin of increased alkaline phosphatase in the urine of rabbits with injured proximal tubules, we studied the phosphatase by an isoenzyme examination, an inhibition test and an inactivation test. Male rabbits were daily injected subcutaneously with cadmium chloride at a dose of 1.5 mg Cd/kg/day. After treatment for three weeks, total activity of alkaline phosphatase and its isoenzyme patterns on agar-gel and disc-gel electrophoresis were examined in the liver, kidney cortex, plasma and urine, and compared with those of the control rabbits. Alkaline phosphatase activity in the urine of the cadmium treated rabbit was about eleven times higher than that of the control (p = less than 0.005), while enzyme activity of plasma showed almost no difference between the two groups. The isoenzyme patterns of alkaline phosphatase in both agar-gel and disc-gel electrophoresis showed that the main band of the isoenzymes of alkaline phosphatase obtained from urine of control rabbits migrated faster than that from plasma, liver, or kidney, while the main isoenzyme from urine of the cadmium group was consistent with the rapid migrating isoenzyme obtained from the kidney. Furthermore, in both groups, alkaline phosphatase activity in plasma was inactivated by the treatments of heat and urea, and inhibited by L-homoarginine, while the enzymes of the kidney and urine were not remarkably effected. The findings suggest that the increased urinary excretion of the enzyme after administration of cadmium to rabbits originates from the kidney.
为了确定近端肾小管损伤的家兔尿中碱性磷酸酶升高的来源，我们通过同工酶检测、抑制试验和失活试验对磷酸酶进行了研究。雄性家兔每天皮下注射氯化镉，剂量为1.5毫克镉/千克/天。治疗三周后，检测肝脏、肾皮质、血浆和尿液中碱性磷酸酶的总活性及其在琼脂糖凝胶和圆盘凝胶电泳上的同工酶谱，并与对照家兔进行比较。镉处理组家兔尿液中的碱性磷酸酶活性比对照组高约11倍（p＜0.005），而两组血浆中的酶活性几乎没有差异。琼脂糖凝胶和圆盘凝胶电泳中碱性磷酸酶的同工酶谱显示，对照家兔尿液中碱性磷酸酶同工酶的主要条带迁移速度比血浆、肝脏或肾脏中的快，而镉处理组尿液中的主要同工酶与肾脏中快速迁移的同工酶一致。此外，在两组中，血浆中的碱性磷酸酶活性经加热和尿素处理后失活，受L-高精氨酸抑制，而肾脏和尿液中的酶没有明显影响。这些发现表明，给家兔施用镉后尿中该酶排泄增加源于肾脏。
