HEPATIC GLUTAMINASE MESSENGER-RNA IS CONFINED TO PART OF THE UREA CYCLE DOMAIN THE ADULT RODENT LIVER LOBULE
HEPATIC GLUTAMINASE MESSENGER-RNA IS CONFINED TO PART OF THE UREA CYCLE DOMAIN THE ADULT RODENT LIVER LOBULE
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DOI：
10.1016/0014-5793(94)01230-x
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发表时间：
1994-12-12
期刊：
影响因子：
3.5
通讯作者：
LAMERS, WH
中科院分区：
文献类型：
--
作者：
MOORMAN, AFM;DEBOER, PAJ;LAMERS, WH
本原位杂交研究描述了正常大鼠肝脏中编码肝转氨酶的mRNA的小叶分布的发育外观。谷氨酰胺酶已被提出为尿素循环提供氨[Haussinger和Gerok（1983）fur. 133，269-275]。因此，预期mRNA的表达（发育）模式与尿素循环酶的表达密切相关。从胚胎第20天起，肝转氨酶mRNA可以检测到沿着整个门静脉中轴，主要表达在汇管区。在出生后第一周结束时获得的成人表型中，转氨酶mRNA不再沿着整个门静脉-中央距离存在，而是局限于相对较小的门静脉周围区域，其中表达沿门静脉-中央方向减少。因此，与表达尿素循环酶的大的门脉周围区域相反，谷氨酰胺酶mRNA表达区域小得多，并且不与谷氨酰胺合成酶mRNA表达的中心周围区域相邻，留下了缺乏谷氨酰胺酶mRNA的小叶中部区域。在成年小鼠肝脏中发现了类似的分布模式。这些观察结果的重要性在于，在肝小叶内，有一个区域不表达谷氨酰胺酶，因此谷氨酰胺不能作为尿素合成的底物。
This in situ hybridization study describes the developmental appearance of the lobular distribution of the mRNA encoding hepatic glutaminase in normal rat liver. Glutaminase has been proposed to provide the urea cycle with ammonia [Haussinger and Gerok (1983) fur. J. Biochem. 133, 269-275]. Hence, the (developmental) pattern of expression of the mRNA would be expected to be closely linked to that of the urea cycle enzymes. From embryonic day 20 onward, hepatic glutaminase mRNA can be detected along the entire porto-central axis, with predominant expression in the portal area. In the adult phenotype, which is acquired at the end of the first postnatal week, glutaminase mRNA is no longer present along the entire porto-central distance but has become confined to a relatively small periportal domain in which the expression decreases in a porto-central direction. Thus, in contrast to the large periportal domain, in which the urea cycle enzymes are expressed, the glutaminase mRNA-expressing domain is much smaller and not contiguous with the glutamine synthase mRNA-expressing pericentral domain, leaving a midlobular area that is devoid of glutaminase mRNA. A similar pattern of distribution was found in adult mouse liver. The significance of these observations is that, within the liver lobules, there is an area in which glutaminase is not expressed and, hence, glutamine can not be the substrate for urea synthesis.