未结合胆红素对大鼠肾皮质切片中对氨基马尿酸转运的抑制作用。

Inhibitory effect of unconjugated bilirubin on p-aminohippurate transport in rat kidney cortex slices.

作者信息

Elías M M, Comín E J, Grosman M E, Galeazzi S A, Rodriguez Garay E A

出版信息

Biochim Biophys Acta. 1982 Dec 22;693(2):265-72. doi: 10.1016/0005-2736(82)90431-x.

Abstract

The effects of unconjugated bilirubin on the accumulation of p-aminohippurate, kinetics of p-aminohippurate uptake, the efflux of pre-accumulated p-aminohippurate and water and electrolyte distribution were investigated in the rat kidney cortical slice. (2) The addition of unconjugated bilirubin to the incubation medium decreased the 60 min slice-to-medium concentration ratio of p-aminohippurate. (3) The decrease in p-aminohippurate accumulation by unconjugated bilirubin was found to be more pronounced by increasing the concentration of pigment in the medium. (4) The rate of uptake of p-aminohippurate as a function of p-aminohippurate concentration differed in aerobiosis and anaerobiosis, and unconjugated bilirubin decreased only the uptake of p-aminohippurate in aerobic conditions. (5) The efflux of pre-accumulated p-aminohippurate decreased when unconjugated bilirubin concentration in the medium was low (10-20 microM) but the efflux increased when the concentration of pigment was much higher (100 microM). (6) The addition of unconjugated bilirubin to the medium (40-100 microM) increased intracellular sodium and total tissue water content, and decreased intracellular potassium and oxygen consumption of tissue. However the slices incubated with low concentration of pigment (20 microM) did not exhibit significative changes in cellular functional parameters. (7) These findings suggest that unconjugated bilirubin impairs p-aminohippurate transport by a complex mechanism that might involve binding of pigment to sites necessary for anion transport, although effects related to pigment toxicity or to its oxidative decomposition are not excluded.

摘要

在大鼠肾皮质切片中研究了未结合胆红素对对氨基马尿酸积累、对氨基马尿酸摄取动力学、预先积累的对氨基马尿酸流出以及水和电解质分布的影响。(2) 向孵育培养基中添加未结合胆红素会降低对氨基马尿酸60分钟的切片与培养基浓度比。(3) 发现通过增加培养基中色素的浓度，未结合胆红素对氨基马尿酸积累的降低更为明显。(4) 在需氧和厌氧条件下，对氨基马尿酸摄取速率作为对氨基马尿酸浓度的函数有所不同，未结合胆红素仅在有氧条件下降低对氨基马尿酸的摄取。(5) 当培养基中未结合胆红素浓度较低（10 - 20 microM）时，预先积累的对氨基马尿酸流出减少，但当色素浓度高得多（100 microM）时，流出增加。(6) 向培养基中添加未结合胆红素（40 - 100 microM）会增加细胞内钠和组织总含水量，并降低细胞内钾和组织耗氧量。然而，用低浓度色素（20 microM）孵育的切片在细胞功能参数上未表现出显著变化。(7) 这些发现表明，未结合胆红素通过一种复杂机制损害对氨基马尿酸转运，该机制可能涉及色素与阴离子转运所需位点的结合，尽管不排除与色素毒性或其氧化分解相关的影响。