QUANTITATIVE PARTITION OF THREONINE OXIDATION IN PIGS - EFFECT OF DIETARY THREONINE
QUANTITATIVE PARTITION OF THREONINE OXIDATION IN PIGS - EFFECT OF DIETARY THREONINE
复制标题
DOI：
10.1152/ajpendo.1990.259.4.e483
复制
发表时间：
1990-10-01
影响因子：
--
通讯作者：
GARLICK, PJ
中科院分区：
文献类型：
--
作者：
BALLEVRE, O;CADENHEAD, A;GARLICK, PJ
苏氨酸（Thr）代谢的动力学方面进行了研究，在8头猪饲养hoursly与饮食含有0.68%（LT组）或0.81%（HT组）的Thr（wt/wt），相应的10和30%的Thr过量，分别与“理想”的饮食。在连续输注L-[U-14 C]-Thr和[1- 13 C]Gly 12 h以及连续输注[1 - 14 C]KB 6 h后，获得Thr、甘氨酸（Gly）和2-酮丁酸（KB）的初级生产（PR）和处置（DR）率。 还监测了Thr向二级库的转移，并从这些中估计了通过L-Thr 3-脱氢酶（DRThr-Gly）和苏氨酸脱氢酶（DRThr-KB）的分解代谢途径的Thr氧化速率。对于LT组，结果为（μ mol·cm·d）。kg-1. h ~（-1）PRThr 314 ±. 3，PRGly 551 .+-. 24，PRKB 41 .+-. 3、DRThr-Gly 22 . ±-. 2和DRThr-KB 7 . ±-. 1.对于HT组，它们是PRThr 301 ±。23，PRGly 598 .+-. 55，PRKB 39 .+-. 4、DRThr-Gly 32 . ±-. 2和DRThr-KB 8 . ±-. 1. Thr摄入量的增加（14 μ mol. kg-1. h-1，P < 0.01）诱导DRThr-Gly和DRThr-KB总和的相应增加（14 μ mol·cm-1，P <0.01）。kg-1. h-1，P < 0.01）。这主要是由于增加的DRThr-Gly（13 μ mol·cm-1）。kg-1. h-1，P < 0.01），DRThr-KB变化无统计学意义。通过比较每种输注类型的不同组织的细胞内与血浆比活度（或富集），显示肝脏是由Thr产生Gly和KB的主要部位。这些数据表明，在饲养生长猪的30%过量的Thr在饮食中不改变分配的Thr氧化，因为80%的Thr氧化发生在整个L-Thr 3-脱氢酶途径的LT和HT组。
Kinetic aspects of threonine (Thr) metabolism were examined in eight pigs fed hoursly with a diet containing either 0.68% (LT group) or 0.81% (HT group) of Thr (wt/wt), a corresponding to 10 and 30% Thr excess, respectively, compared with an "ideal" diet. Primary production (PR) and disposal (DR) rates were obtained for Thr, glycine (Gly), and 2-ketobutyrate (KB) after a 12-h continuous infusion of L-[U-14C]-Thr together with [1-13C]Gly and a 6-h continuous infusion of [1-14C]KB. Transfer of Thr into secondary pools was also monitored, and from these the rates of Thr oxidation through the catabolic pathways of L-Thr 3-dehydrogenase (DRThr-Gly) and threonine dehydratase (DRThr-KB) were estimated. For the LT group the results were (.mu.mol .cntdot. kg-1 .cntdot. h-1) PRThr 314 .+-. 3, PRGly 551 .+-. 24, PRKB 41 .+-. 3, DRThr-Gly 22 .+-. 2, and DRThr-KB 7 .+-. 1. For the HT group they were PRThr 301 .+-. 23, PRGly 598 .+-. 55, PRKB 39 .+-. 4, DRThr-Gly 32 .+-. 2, and DRThr-KB 8 .+-. 1. The increase in Thr intake (14 .mu.mol .cntdot. kg-1 .cntdot. h-1, P < 0.01) induced a commensurate increase in the sum of DRThr-Gly and DRThr-KB (14 .mu.mol .cntdot. kg-1 .cntdot. h-1, P < 0.01) when liver was used as the precursor pool. This was mainly due to the increased DRThr-Gly (13 .mu.mol .cntdot. kg-1 .cntdot. h-1, P < 0.01); the change in DRThr-KB was not statistically significant. By comparison of intracellular-to-plasma ratios of specific activities (or enrichments) for different tissues with each type of infusion, liver was shown to be the major site of production of Gly and KB from Thr. These data suggest that in fed growing pigs a 30% excess of Thr in the diet does not alter the partition of Thr oxidation, since 80% of Thr oxidation occurs throughout the L-Thr 3-dehydrogenase pathway for both LT and HT groups.