Kapur Priya, Kaur Kamaljit, Mahmood Akhtar
Department of Biochemistry, Panjab University, Chandigarh-160 014, India.
J Appl Toxicol. 2005 Sep-Oct;25(5):361-4. doi: 10.1002/jat.1079.
The effect of feeding lead (50 mg kg(-1) body weight) daily for 7 days on the development of various brush border enzymes in the intestine has been studied. The activities of brush border sucrase (P < 0.001), lactase (P < 0.001), gamma-glutamyl transpeptidase (P < 0.05) and leucine aminopeptidase were reduced (P < 0.05), whereas the alkaline phosphatase level was augmented (P < 0.05) in lead fed rats compared with controls. Kinetic studies with sucrase revealed a low Vmax (0.224 in control and 0.160 units mg(-1) protein in lead exposed) with no change in Km (12.6-13.5 mM). Western blot analysis for alkaline phosphatase yielded intense staining of enzyme protein in lead fed rats compared with controls, however, the intensity of the antigen signal was reversed for sucrase under these conditions. These findings suggest that ingestion of lead may interfere with the crypt cell differentiation process thus affecting enzyme functions in the rat intestine.
研究了连续7天每天给大鼠喂食铅（50毫克/千克体重）对肠道中各种刷状缘酶发育的影响。与对照组相比，喂食铅的大鼠刷状缘蔗糖酶（P<0.001）、乳糖酶（P<0.001）、γ-谷氨酰转肽酶（P<0.05）和亮氨酸氨肽酶的活性降低（P<0.05），而碱性磷酸酶水平升高（P<0.05）。对蔗糖酶的动力学研究显示，最大反应速度（Vmax）较低（对照组为0.224，铅暴露组为0.160单位/毫克蛋白质），米氏常数（Km）无变化（12.6 - 13.5毫摩尔）。碱性磷酸酶的蛋白质印迹分析表明，与对照组相比，喂食铅的大鼠中酶蛋白染色强烈，然而，在这些条件下蔗糖酶的抗原信号强度则相反。这些发现表明，摄入铅可能会干扰隐窝细胞分化过程，从而影响大鼠肠道中的酶功能。
