Linked Life Data

19403714

Source:http://linkedlifedata.com/resource/pubmed/id/19403714

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
6
pubmed:dateCreated
2009-5-21
pubmed:abstractText
The high energetic demands and metabolism of amino acids (AA) within the lactating mammary gland have been ascribed to the requirements for milk component synthesis and tissue maintenance. Our objective in this work was to assess rates of protein synthesis from several AA so that the energetic costs of tissue maintenance could be better reflected. Lactating goats (n = 4) were given staggered infusions of 5 labeled forms of phenylalanine (Phe) initiated at 30, 12, 9, 6, and 3 h before goats were killed. [5-(13)CH(3)] Methionine (Met), [1-(13)C] leucine, and [1-(13)C] valine were also infused for 30 h, during which time, the glands were milked hourly and arteriovenous flux measurements were performed the last 6 h. A dynamic, compartmental model capable of simulating fluxes of AA through extracellular and intracellular free, slow and fast turnover tissue-bound, and milk protein pools was developed and fitted to the observed data. The udder removed 81% of the Phe present in plasma using 31% for milk protein synthesis and releasing 66% back into plasma. Transamination accounted for 40% of Phe flux in the mammary and transmethylation accounted for a portion of mammary Met flux. Mammary tissue protein synthesis was >300% the value of milk protein synthesis with fractional protein synthesis rates >130%/d. Assuming 4 mol of ATP/mol of peptide bond formed, we estimate that approximately 50% of ATP generated by the lactating mammary glands is used for synthesis of tissue (nonmilk) protein.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Jun
pubmed:issn
1541-6100
pubmed:author
pubmed:issnType
Electronic
pubmed:volume
139
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
1118-27
pubmed:meshHeading
pubmed:year
2009
pubmed:articleTitle
High rates of mammary tissue protein turnover in lactating goats are energetically costly.
pubmed:affiliation
Department of Dairy Science, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061, USA. MHanigan@vt.edu
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, Non-P.H.S., Research Support, Non-U.S. Gov't