Linked Life Data

241864

Source:http://linkedlifedata.com/resource/pubmed/id/241864

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
4
pubmed:dateCreated
1976-1-29
pubmed:abstractText
Induction of tyrosine aminotransferase (TAT) (EC 2.6.1.5) by hydrocortisone was studied during cofactor (pyridoxal phosphate) depletion in hepatoma-bearing BUF strain female rats. Pairs of rats were matched for weight and age and one from each pair was fed ad libitum a diet lacking pyridoxine; the other (referred to as "pair-fed") was given the same diet supplemented with the vitamin, with the amount restricted to that consumed by the matched animal on the deficient diet. All animals were inoculated with Morris hepatoma no. 7777 cell after 21 days on the respective diets. TAT specific activity was determined weekly in host liver and hepatoma, in the presence and absence of cofactor, before and after the administration of hydrocortisone. Free and bound pyridoxal phosphate was estimated enzymatically. The average weight of hepatomas from pair-fed animals was 1.5-fold to twofold greater than that of hepatomas from animals on deficient diets. TAT activity of hepatomas was two times greater than that of host liver, and lack of dietary pyridoxine was without effect. Hormonal induction of enzymatic activity was maximal after the first week of tumor growth and subsequently reached minimal values. In pair-fed animals, tumor TAT was approximately 60% saturated with cofactor. In vitamin-deficient animals, only 6% of the tumor enzyme was saturated with the cofactor. The percent saturation of host liver TAT varied, with minimal values found in the vitamin-deficient animals. Hepatic and tumor pyridoxal phosphate content of pair-fed animals was unusually high (10 mug/g); in vitamin-deficient animals, only the coenzyme content of hepatomas was high (7.0 mug/g). The results showed that presence of the tumor altered the a) specific activity level of TAT and tissue content of cofactor, b) pattern of hormonal induction of the enzyme, and c) effects of the absence of dietary pyridoxine on TAT induction observed in animals without tumors.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Oct
pubmed:issn
0027-8874
pubmed:author
pubmed:issnType
Print
pubmed:volume
55
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
839-41
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
1975
pubmed:articleTitle
Hormonal induction of tyrosine aminotransferase activity in host liver and hepatoma no. 7777 of normal and cofactor-depleted animals.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S.