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PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
3
pubmed:dateCreated
2006-3-1
pubmed:abstractText
Absorption and metabolism of the Met hydroxy analog 2-hydroxy-4-methylthiobutyrate (HMTBA) was examined using stable isotopes. In the first trial, Dl[1-13C]HMTBA was infused for 6 h (7.4 micromol/min) into the abomasum, and [2H3]Met was infused into the mesenteric vein, of 4 lambs prepared with vascular catheters across the splanchnic bed. Daily, lambs were offered 35 g of a mixed forage-concentrate feed/kg. Recovery of HMTBA at the portal vein was 87%, and of this, 63% bypassed the liver. In contrast, hepatic extraction of Met equaled or exceeded net absorption. Only small quantities of Met synthesized from HMTBA were exported from either the digestive tract or liver, but there was substantial and significant input from posthepatic tissues. In a second experiment, 3 of the lambs were killed following 4-h infusions of DL[1-13C]HMTBA and [2H3]Met with enrichments monitored in 15 tissues. Only kidney showed [1-13C]Met enrichment higher than plasma, which suggests that it must be a primary source of plasma Met derived from HMTBA. Based on comparison of plasma and intracellular [1-13C]:[2H3]Met enrichments, all tissues synthesized Met from HMTBA but to significantly different extents. The lowest values were for muscle, skin, brain, and lung; intermediate conversions occurred in rumen, omasum, abomasum, duodenum, jejunum, ileum, and cecum; and the greatest synthesis, equivalent to 22 to 24% of Met entry into cells, was observed for liver and kidney. Therefore, although liver and kidney both converted HMTBA to Met, it was retained by the former and exported by the latter. Under these experimental conditions, synthesis of Met from HMTBA completely eliminated use of dietary Met.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Mar
pubmed:issn
1525-3198
pubmed:author
pubmed:issnType
Electronic
pubmed:volume
89
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
1072-80
pubmed:meshHeading
pubmed:year
2006
pubmed:articleTitle
Absorption of 2-hydroxy-4-methylthiobutyrate and conversion to methionine in lambs.
pubmed:affiliation
Rowett Research Institute, Bucksburn, Aberdeen, AB21 9SB, UK. gel@rri.sari.ac.uk
pubmed:publicationType
Journal Article