Effect of orotic acid on beta 1,4-galactosyltransferase during liver regeneration.
Effect of orotic acid on beta 1,4-galactosyltransferase during liver regeneration.
复制标题
乳清酸对肝再生过程中 β1,4-半乳糖基转移酶的影响。
DOI：
10.1093/carcin/14.6.1095
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发表时间：
1993
期刊：
影响因子：
4.7
通讯作者：
Rajalakshmi,S
中科院分区：
文献类型：
--
作者：
Sharma,RK;Pascale,RM;Narasimhan,S;Rajalakshmi,S
本研究旨在了解乳清酸（OA）对β 1，4-半乳糖基转移酶（GalTase）表达的影响，GalTase是一种参与将半乳糖从UDP-半乳糖转移到糖蛋白或糖脂的非还原末端N-乙酰葡萄糖胺的酶。给大鼠喂含1%OA的半合成饲料2周，并通过三分之二部分肝切除术（PH）刺激肝脏再生。分别于PH前、PH后12、24、48、72 h和PH后10 d测定肝组织GalTase活性和GalTase mRNA稳态水平。数据显示，在手术后12小时之前，对照组和OA喂养组中GalTase的肝脏活性均未改变，但在此时间段后开始增加。在对照组中的逐步增加，看到整个实验期间后PH。另一方面，在OA-喂养组PH后24小时，最初的增加看到了24小时后被捕，并在整个实验期间的其余部分的活动仍然受到抑制。补充1%OA饲料与0.3%腺嘌呤，这是已知的逆转OA诱导的核苷酸池大小的不平衡，解除了抑制GalTase活性。在肝再生过程中研究的所有时间点，肝mRNA的稳态水平与GalTase的活性相关。OA喂养组中GalTase mRNA转录水平的降低可能不是由于mRNA合成和/或降解的一般抑制，如对照组和OA喂养组中β-半乳糖苷2，6-唾液酸转移酶表达的比较所揭示的。因此，该研究表明，核苷酸库的不平衡，如OA诱导的不平衡，可能通过调节糖基转移酶在糖基化的调节中发挥作用。
The study was designed to understand the effect of orotic add (OA) on the expression of β1,4-galactosyltransferase (GalTase), an enzyme involved in the transfer of galactose from UDP-galactose to a non-reducing terminalN-acetylglucosamine of a glycoprotein or glycolipid. Rats were fed a semisynthetic diet containing 1% OA for 2 weeks and the livers were stimulated to regenerate by two-thirds partial hepatectomy (PH). The level of activity of the enzyme and the steady-state level of hepatic mRNA transcripts of GalTase were determined prior to PH and at 12, 24, 48, 72 h and 10 days after the surgery. The data show that the hepatic activity of GalTase is unaltered in both the control and OA-fed groups until 12 h following surgery, but begins to increase after this time period. In the control group a progressive increase was seen throughout the experimental period following PH. On the other hand in the OA-fed group 24 h after PH the initial increase seen up to 24 h was arrested later on and the activity remained inhibited throughout the rest of the experimental period. The supplementation of 1% OA diet with 0.3% adenine, which is known to reverse the OA-induced imbalance in the nucleotide pool sizes, relieved the inhibition of GalTase activity. The steady-state level of hepatic mRNA paralleled the activity of GalTase at all the time points studied during liver regeneration. The reduction in the level of mRNA transcripts of GalTase in the OA-fed group may not be due to either a general inhibition of synthesis and/or degradation of mRNAs as revealed by a comparison of the expression of β-galactoside 2,6-sialyltransferase in both the control and OA-fed groups. The study thus suggests an imbalance in nucleotide pools, such as the one induced by OA, may play a role in the regulation of glycosylation by modulating the glycosyltransferases.