Uridine catabolism in Kupffer cells, endothelial cells, and hepatocytes.
Uridine catabolism in Kupffer cells, endothelial cells, and hepatocytes.
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库普弗细胞、内皮细胞和肝细胞中的尿苷分解代谢。
DOI：
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发表时间：
1985
期刊：
影响因子：
--
通讯作者：
W. Gerok
中科院分区：
文献类型：
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作者：
A. Holstege;H. Leser;J. Pausch;W. Gerok
通过离心淘洗分离枯否细胞、内皮细胞和肝细胞。在三种不同肝细胞类型的悬浮液中监测尿嘧啶形成速率（尿苷催化转化的第一步）。枯否细胞尿苷磷酸化率最高。加入核苷后15 min，尿嘧啶中的标记分别占枯否细胞、内皮细胞和肝细胞培养基中总放射性的51%、13%和19%。如果校正枯否细胞污染，肝细胞悬液表现出与内皮细胞相似的活性。与非实质细胞相反，肝细胞持续从孵育培养基中清除尿嘧啶。枯否细胞和内皮细胞缺乏尿嘧啶消耗，表明尿嘧啶是这些细胞中尿苷催化剂的终产物。枯否细胞和内皮细胞在[2- 14 C]尿苷存在下孵育时不产生放射性CO2。然而，肝细胞能够将尿苷降解为CO2、β-丙氨酸和氨，这通过标记核苷的挥发性放射性活性形成来证明。几乎没有检测到任何不同类型的细胞从胸苷形成胸腺嘧啶或从胞苷形成胞嘧啶、尿嘧啶或尿苷。这些结果与大鼠肝脏中的低胸苷磷酸化和胞苷脱氨一致。我们的研究表明，库普弗细胞，内皮细胞和肝细胞的合作，在门静脉血尿苷的分解与尿苷磷酸化主要发生在库普弗细胞和尿嘧啶catalysts局限于肝实质细胞。
Kupffer cells, endothelial cells, and hepatocytes were separated by centrifugal elutriation. The rate of uracil formation from [2-14C]uridine, the first step in uridine catabolism, was monitored in suspensions of the three different liver cell types. Kupffer cells demonstrated the highest rate of uridine phosphorolysis. 15 min after the addition of the nucleoside the label in uracil amounted to 51%, 13%, and 19% of total radioactivity in the medium of Kupffer cells, endothelial cells, and hepatocytes, respectively. If corrected for Kupffer cell contamination, hepatocyte suspensions demonstrated similar activities as endothelial cells. In contrast to non-parenchymal cells, hepatocytes continuously cleared uracil from the incubation medium. The lack of uracil consumption by Kupffer cells and endothelial cells points to uracil as the end-product of uridine catabolism in these cells. Kupffer cells and endothelial cells did not produce radioactive CO2 upon incubation in the presence of [2-14C]uridine. Hepatocytes, however, were able to degrade uridine into CO2, beta-alanine, and ammonia as demonstrated by active formation of volatile radioactivity from the labeled nucleoside. There was almost no detectable formation of thymine from thymidine or of cytosine, uracil, or uridine from cytidine by any of the different cell types tested. These results are in line with low thymidine phosphorolysis and cytidine deamination in rat liver. Our studies suggest a co-operation of Kupffer cells, endothelial cells, and hepatocytes in the breakdown of uridine from portal vein blood with uridine phosphorolysis predominantly occurring in Kupffer cells and with uracil catabolism restricted to parenchymal liver cells.
嘧啶核苷磷酸化酶的特异性和 5-氟-2-脱氧尿苷的磷酸解。
影响因子：
11.2
作者：
Woodman,PW;Sarrif,AM;Heidelberger,C
通讯作者：
Heidelberger,C