Adaptive regulation of intestinal lysine metabolism

Goudoever, Johannes B. van; Stoll, Barbara J.; Henry, J. E.; Burrin, Douglas G.; Reeds, Peter J.

doi:10.1073/pnas.200371497

Cited by 136 publications

(111 citation statements)

References 36 publications

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“…Oxidation of essential amino acids by the PDV has been reported in studies with young animals (i.e., lysine, leucine) (43,44,50,51). Phenylalanine oxidation by the PDV accounted for nearly 40% of whole body phenylalanine oxidation in the current study.…”

Section: Discussionsupporting

confidence: 68%

Somatotropin-induced protein anabolism in hindquarters and portal-drained viscera of growing pigs

Bush

Burrin

Suryawan

et al. 2003

American Journal of Physiology-Endocrinology and Metabolism

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Arterial, portal venous, and vena cava whole blood samples, breath samples, and blood flow measurements were obtained for determination of tissue and whole body phenylalanine kinetics under steady-state conditions. In the fed state, ST treatment decreased whole body phenylalanine flux, oxidation, and protein degradation without altering protein synthesis, resulting in an improvement in whole body net protein balance. Blood flow to the HQ (ϩ80%), but not to the PDV, was increased with ST treatment. In the HQ and PDV, ST increased phenylalanine uptake (ϩ44 and ϩ23%, respectively) and protein synthesis (ϩ43 and ϩ41%, respectively), with no effect on protein degradation. In ST-treated and control pigs, phenylalanine was oxidized in the PDV (34-43% of enteral and arterial sources) but not the HQ. In both treatment groups, dietary (40%) rather than arterial (10%) extraction of phenylalanine predominated in gut amino acid metabolism, whereas localized blood flow influenced HQ amino acid metabolism. The results indicate that ST increases protein anabolism in young, growing swine by increasing protein synthesis in the HQ and PDV, with no effect on protein degradation. Differing results between the whole body and the HQ and PDV suggest that the effect of ST treatment on protein metabolism is tissue specific.

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Section: Discussionsupporting

confidence: 68%

Somatotropin-induced protein anabolism in hindquarters and portal-drained viscera of growing pigs

Bush

Burrin

Suryawan

et al. 2003

American Journal of Physiology-Endocrinology and Metabolism

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“…Our previous studies have shown that GIT extensively metabolize dietary indispensable amino acids, namely lysine, threonine, and leucine (24 -26). In the case of methionine, our studies and those of others suggest that substantial metabolism and even oxidation of dietary methionine occurs in the gut (26,27). However, the extent of transmethylation and transsulfuration in the GIT and its relative contribution to whole-body methionine metabolism has not been established.…”

mentioning

confidence: 50%

“…Methionine and cystine contents were 0.52% and 0.61%, respectively, providing a daily intake of 0.25 g methionine/kg and 0.31 g of cystine/kg. At 20 days of age, the piglets (n ϭ 16) were surgically implanted with catheters as described (26,41). One week after surgery, each piglet received ID and IV tracer infusions on two different days in a randomized, cross-over design with at least one day between the ID and IV infusions.…”

Section: Methodsmentioning

confidence: 99%

Methionine transmethylation and transsulfuration in the piglet gastrointestinal tract

Riedijk

Stoll

Chacko

et al. 2007

Proc. Natl. Acad. Sci. U.S.A.

125

103

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Methionine is an indispensable sulfur amino acid that functions as a key precursor for the synthesis of homocysteine and cysteine. Studies in adult humans suggest that splanchnic tissues convert dietary methionine to homocysteine and cysteine by means of transmethylation and transsulfuration, respectively. Studies in piglets show that significant metabolism of dietary indispensable amino acids occurs in the gastrointestinal tissues (GIT), yet the metabolic fate of methionine in GIT is unknown. We show here that 20% of the dietary methionine intake is metabolized by the GIT in piglets implanted with portal and arterial catheters and fed milk formula. Based on analyses from intraduodenal and intravenous infusions of [1-13 C]methionine and [ 2 H3]methionine, we found that the whole-body methionine transmethylation and remethylation rates were significantly higher during duodenal than intravenous tracer infusion. First-pass splanchnic metabolism accounted for 18% and 43% of the whole-body transmethylation and remethylation, respectively. Significant transmethylation and transsulfuration was demonstrated in the GIT, representing Ϸ27% and Ϸ23% of whole-body fluxes, respectively. The methionine used by the GIT was metabolized into homocysteine (31%), CO 2 (40%), or tissue protein (29%). Cystathionine ␤-synthase mRNA and activity was present in multiple GITs, including intestinal epithelial cells, but was significantly lower than liver. We conclude that the GIT consumes 20% of the dietary methionine and is a significant site of net homocysteine production. Moreover, the GITs represent a significant site of whole-body transmethylation and transsulfuration, and these two pathways account for a majority of methionine used by the GITs.cystathionine ␤-synthase ͉ homocysteine ͉ intestine

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“…From 08.00 to 14.00 hours, pigs were offered meals at hourly intervals, and the meal was the equivalent of one twenty-fourth of the daily intake (45 g/kg BW). Immediately after the first meal, piglets received a constant infusion of [1-13 C]methionine, suspended in water via the gastric catheter at a rate of about 0·25 ml/min to provide [1][2][3][4][5][6][7][8][9][10][11][12][13] C]methionine at 7·0 mmol/kg BW per h. After the tracer infusion was started, the piglets continued to receive hourly meals. Arterial and portal blood samples were taken at hourly intervals until 6 h of tracer infusion, and all the blood samples were immediately placed on ice.…”

Section: Infusion Protocol and Blood Collectionmentioning

confidence: 99%

Effects ofdl-2-hydroxy-4-methylthiobutyrate on the first-pass intestinal metabolism of dietary methionine and its extra-intestinal availability

et al. 2010

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The present study was conducted in a one-factorial arrangement to determine the effects of DL-2-hydroxy-4-methylthiobutyrate (DL-HMTB) on the first-pass intestinal metabolism of dietary methionine and its extra-intestinal availability. Barrows (n 6; aged 35 d; weight 8·6 kg), implanted with arterial, portal, mesenteric and gastric catheters, were fed a diet containing DL-methionine (DL-MET) or DL-HMTB once hourly and infused intramesenterically with 1 % p-aminohippurate and intragastrically with [1-13 C]methionine at 7·0 mmol/kg body weight per h. Arterial and portal blood samples were taken at hourly intervals until 6 h of tracer infusion and pigs was then killed for collection of muscle, intestine, liver and kidney samples. The net portal appearance of methionine, expressed as the fraction of ingested directly available L-methionine, was higher (P,0·05) in the DL-HMTB than in the DL-MET diet, and there was no difference (P¼ 0·26) in the fractional portal balance of [1-13 C]methionine between the diets. [1-13 C]methionine enrichment (tracer:tracee ratio; mol/100 mol amino acid) in the jejunum, arterial and portal plasma, liver, kidney and muscle was also not different (P.0·05) between the groups. Over the 6 h period after the start of feeding, the average concentration of citrulline both in the arterial and portal plasma was higher (P,0·05) in the DL-HMTB than in the DL-MET group, and arterial plasma ornithine and taurine concentration was also higher (P,0·05) in the DL-HMTB than in the DL-MET group. However, plasma urea concentration both in the arterial and portal vein was lower (P, 0·05) in the DL-HMTB than in the DL-MET group. These results suggested that the potential difference in the first-pass use of methionine by the intestine between the DL-HMTB and DL-MET diets might affect intestinal and systemic metabolism of other amino acids, which may provide new important insights into nutritional efficiency of different methionine sources.DL-2-Hydroxy-4-methylthiobutyrate: First-pass intestinal metabolism: Extra-intestinal availabilityThe small intestine is a highly differentiated and complex organ, which is not only responsible for the terminal digestion and absorption of nutrients, but also plays an important role in the synthesis, conversion and catabolism of amino acids (1) . Because the apical and basolateral membranes of each enterocyte are chemically, biochemically and physically distinct (2) , an enterocyte can selectively receive nutrients from two sources: the arterial blood across its basolateral membrane and the intestinal lumen across its brush-border membrane. Historically, it is assumed that the primary fate of essential amino acids is to protein synthesis in the target organs; however, intriguing data have demonstrated that catabolism dominates the first-pass utilisation of these amino acids by the gut (3) . Because the extensive catabolism of dietary essential amino acids by the small intestine results in a decrease in their nutritional efficiency (1,3,4) , the question whether the catabolism ...

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Adaptive regulation of intestinal lysine metabolism

Cited by 136 publications

References 36 publications

Somatotropin-induced protein anabolism in hindquarters and portal-drained viscera of growing pigs

Somatotropin-induced protein anabolism in hindquarters and portal-drained viscera of growing pigs

Methionine transmethylation and transsulfuration in the piglet gastrointestinal tract

Effects ofdl-2-hydroxy-4-methylthiobutyrate on the first-pass intestinal metabolism of dietary methionine and its extra-intestinal availability

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