Hepatic glutamate transport and glutamine synthesis capacities are decreased in finished vs. growing beef steers, concomitant with increased GTRAP3-18 content

Huang, Jing; Yang, Jia; Li, Q.; Burris, W. R.; Bridges, Phillip J.; Matthews, J. C.

doi:10.1007/s00726-018-2540-8

Cited by 4 publications

(20 citation statements)

References 65 publications

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“…The animal management regimen and model for steers that yielded the tissues for the present experiment have been reported (Huang et al, 2018). Briefly, 16 weaned, predominately Angus, steers of similar shrunk (denied feed and water for 14 h) BW (209 ± 29.4 kg) were randomly assigned (n = 8) to either Growing (target BW = 295 kg) or Finished (target BW = 568 kg) treatment groups.…”

Section: Animal Model Slaughter Tissue Collection and Carcass Evaluationmentioning

confidence: 99%

“…Steers had ad libitum access to fresh water and a vitamin-mineral mix (UK IRM Beef Cattle Vitamin-mineral Mix, Burkmann Mill, Inc., Danville, KY). As previously described in detail (Huang et al, 2018), Growing steers required 57 ± 7 d to reach their final BW (301 ± 7.06 kg) and 261 ± 12 d were required for Finished steers to reach their final BW (576 ± 36.9 kg). As planned, the ADG did not differ (1.51 vs. 1.46 kg/d) in Growing vs.…”

Section: Animal Model Slaughter Tissue Collection and Carcass Evaluationmentioning

confidence: 99%

“…The methods used for the slaughter, tissue collection, and carcass evaluation of Growing and Finished steers have been reported (Huang et al, 2018). Briefly, one steer per day was slaughtered, from alternating treatment groups.…”

Section: Animal Model Slaughter Tissue Collection and Carcass Evaluationmentioning

confidence: 99%

“…After the HCW was recorded, liver, LD (between 12th and 13th rib) muscle and its adjacent SA tissue were collected as described (Brown et al, 2009). For determination of GSH content (Huang et al, 2018), fresh tissues were homogenized in 5% ice-cold metaphosphoric acid solution followed by centrifugation at 3,000 × g, 4°C for 10 min. The supernatant was collected and stored at −80°C overnight for next day assay (see below).…”

Section: Animal Model Slaughter Tissue Collection and Carcass Evaluationmentioning

confidence: 99%

“…In neurons, the interaction between GTRAP3-18 and ARL6IP1 affects EAAC1 activity and cellular GSH levels (Watabe et al, 2008;Aoyama and Nakaki 2012). In the liver of finished vs. growing beef steers, system X AG − activity, EAAC1 content, and glutamine synthetase (GS) activity and content are decreased; GTRAP3-18 and ARL6IP1 contents are increased; whereas GSH and GLT-1 contents do not differ (Huang et al, 2018). The goals of this study were to (1) test the hypothesis that the content of GSH in longissimus dorsi (LD) and subcutaneous adipose (SA) tissues would be less in these finished vs. growing steers and (2) gain insight into the mechanisms by which tissue GSH content was achieved by elucidating related mechanisms.…”

Section: Introductionmentioning

confidence: 99%

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Glutathione content and expression of proteins involved with glutathione metabolism differs in longissimus dorsi, subcutaneous adipose, and liver tissues of finished vs. growing beef steers1

Huang

Yang

et al. 2018

Journal of Animal Science

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Increased tissue redox state may result in sub-optimal growth. Our goal was to determine if glutathione (GSH) content and expression of proteins involved with GSH metabolism change in longissimus dorsi (LD), subcutaneous adipose (SA), and liver tissues of growing vs. finishing steer phenotypes. Tissues were taken from 16 Angus steers (BW = 209 ± 29.4 kg) randomly assigned (n = 8) to develop through Growing (final BW = 301 ± 7.06 kg) vs. Finished (final BW = 576 ± 36.9 kg) growth phases, and at slaughter had achieved different rib-eye area (REA) (53.2, 76.8 cm2), marbling scores (296, 668), and 12th rib adipose thickness (0.54, 1.73 cm), respectively (Amino Acids, doi:10.1007/s00726-018-2540-8). GSH content (mg/g wet tissue) was determined by a commercial assay and the relative content of target protein and mRNA in tissue homogenates was determined by Western blot and reverse-transcribed PCR analyses, respectively. The effect of growth phase (Finished vs. Growing) was assessed by ANOVA using the GLM procedure of SAS. The LD of Finished steers had more (P < 0.04) GSH (42%) and GSH synthesizing (GCLC, 61%; GCLM, 21%) and metabolizing (GPX1, 42%; GPX3, 73%; GGT1, 56%) enzymes, and less (P < 0.02) GPX2 (46%), EAAC1 (30%) and glutamine synthetase (GS) (28%), whereas GTRAP3-18 and ARL6IP1 did not differ (P > 0.57). Principal component analysis found that GSH content of LD was associated with REA and marbling score. The SA of Finished steers had less (P < 0.04) GSH (38%), GSH metabolizing (GPX4, 52%; GGT1, 71%) enzyme mRNA, and GTRAP3-18 (123%) and ARL6IP1 (43%), whereas the mRNA content of GSH-synthesizing enzymes and content of EAAC1 and GS did not differ (P > 0.32). The liver of Finished steers had less (P < 0.02) mRNA content of GSH synthesizing (GCLC, 39%; GSS 29%) and metabolizing (GPX1, 30%) enzymes, and more (P < 0.01) GSTM1 metabolizing enzyme (114%). The change in GSH content as steers fattened indicate an increased antioxidant capacity in the LD of Finished steers, and a decreased antioxidant capacity in SA, consistent with changes in enzyme and transporter expression. Changes in liver enzyme and transporter expression were consistent with no change in GSH content. The relationship of EAAC1 regulatory proteins (GTRAP3-18, ARL6IP1) to GSH, EAAC1, and GS content differs and changes as Growing steers develop into Finished phenotypes. These findings provide mechanistic insight into how antioxidant capacity occurs in tissues of economic and metabolic importance as cattle fatten.

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Section: Animal Model Slaughter Tissue Collection and Carcass Evaluationmentioning

confidence: 99%

Section: Animal Model Slaughter Tissue Collection and Carcass Evaluationmentioning

confidence: 99%

Section: Animal Model Slaughter Tissue Collection and Carcass Evaluationmentioning

confidence: 99%

Section: Animal Model Slaughter Tissue Collection and Carcass Evaluationmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Glutathione content and expression of proteins involved with glutathione metabolism differs in longissimus dorsi, subcutaneous adipose, and liver tissues of finished vs. growing beef steers1

Huang

Yang

et al. 2018

Journal of Animal Science

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Nutrition and Metabolism: Foundations for Animal Growth, Development, Reproduction, and Health

2021

Advances in Experimental Medicine and Biology

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Gene expression profiling indicates a shift in ammonia assimilation capacity along the hepatic acinus induced by different forms of selenium in vitamin–mineral mixes fed to beef steers grazing on toxic endophyte-infected tall fescue

2023

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Recently, we demonstrated that supplementing (with 3 mg Se per day) the diets of growing beef steers grazing on Se-deficient toxic endophyte-infected tall fescue-based forage with either organic Se (OSe, SEL-PLEX) or a 1:1 blend (MIX) of OSe and inorganic Se (ISe, sodium selenite) in vitamin–mineral mixes, rather than inorganic forms of Se, ameliorated several classic serum symptoms of fescue toxicosis. Importantly, higher levels of hepatic glutamine synthetase activity were observed in MIX and OSe steers. Accordingly, transcriptome level and targeted mRNA expression analyses were conducted on the same liver tissue to determine if Se treatments affected other hepatic metabolic pathways, especially those that are responsible for supplying substrates of glutamine synthetase. The effect of ISe, OSe, and MIX treatments (n = 8/treatment) on the relative abundances of mRNA [determined using microarray and real-time reverse-transcription PCR (RT-PCR)] and protein (determined using Western blotting) in liver tissue was assessed by ANOVA. Fisher’s protected LSD procedure was used to separate treatment means, with significance being declared at p ≤ 0.05. Microarray analysis identified (p< 0.01, false discovery rate of< 33%) 573 annotated differentially expressed gene (DEG) transcripts. Canonical pathway analysis identified the DEGs that are central to glutamine and glutamate biosynthesis/degradation and proline biosynthesis. Targeted RT-PCR analyses found that MIX and OSe steers had lower periportal ammonia-assimilation and urea-synthesizing capacities (lower glutaminase 2, key ornithine cycle enzymes, and mitochondrial ornithine/citrulline exchanger mRNA) than ISe steers. In addition, MIX and OSe steers had a higher capacity for pericentral ammonia assimilation (higher glutamine synthetase activity) and a higher capacity for the production of glutamate in pericentral hepatocytes from α-ketoglutarate (higher levels of glutamine dehydrogenase, and decreased levels of arginase 2 and ornithine aminotransferase and mRNA). The form of supplemental Se also affected steers’ capacity for hepatic proline metabolism, with OSe steers having a higher capacity for proline synthesis and MIX steers having a higher capacity for pyroline-5-carboxylate synthesis. In conclusion, supplementing the diets of growing beef steers grazing on toxic endophyte-infected tall fescue with MIX and OSe in vitamin–mineral mixes, rather than with inorganic forms of Se, shifts hepatic ammonia assimilation from periportal urea production to pericentral glutamine production, thus potentially increasing whole-animal N efficiency by increasing the supply of hepatic-synthesized glutamine.

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Hepatic glutamate transport and glutamine synthesis capacities are decreased in finished vs. growing beef steers, concomitant with increased GTRAP3-18 content

Cited by 4 publications

References 65 publications

Glutathione content and expression of proteins involved with glutathione metabolism differs in longissimus dorsi, subcutaneous adipose, and liver tissues of finished vs. growing beef steers1

Glutathione content and expression of proteins involved with glutathione metabolism differs in longissimus dorsi, subcutaneous adipose, and liver tissues of finished vs. growing beef steers1

Nutrition and Metabolism: Foundations for Animal Growth, Development, Reproduction, and Health

Gene expression profiling indicates a shift in ammonia assimilation capacity along the hepatic acinus induced by different forms of selenium in vitamin–mineral mixes fed to beef steers grazing on toxic endophyte-infected tall fescue

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