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PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
3
pubmed:dateCreated
1996-12-17
pubmed:abstractText
Previous control studies carried out in children showed that respiratory infection alters riboflavin metabolism and leads to excessive urinary losses of the vitamin. In order to understand the nature of biochemical changes in riboflavin metabolism during respiratory infection, a study was carried out using the mouse as the experimental model, and Klebsiella pneumoniae as the infective organism. Mice were fed on either a low (0.5 mg/kg)- or high (13.3 mg/kg)-riboflavin semi-synthetic diet. Infection resulted in a 5-6-fold higher excretion of riboflavin in the urine of mice fed on the low-riboflavin diet. Higher erythrocyte FAD levels and lower liver FAD levels were also observed during infection. Of the four enzymes involved in the synthesis and breakdown of the flavin coenzymes studied, the activity of hepatic flavokinase (ATP: riboflavin 5'-phosphotransferase; EC 2.7.1.26) was significantly lower, and that of FAD synthetase (ATP: FMN adenylyltransferase; EC 2.7.7.2) was higher during riboflavin restriction and infection. The activity of FMN (acid) phosphatase (EC 3.1.3.2) was unchanged, whereas FAD (nucleotide) pyrophosphatase (EC 3.6.1.9) activity was significantly higher both with the low-riboflavin diet and during infection. Thyroid hormone is known to modulate flavokinase activity and, hence, thyroid status was assessed. Plasma triiodothyronine (T3) levels were not affected, but thyroxine levels were lower in the mice fed on the low-riboflavin diet. However, plasma T3 was significantly lower during infection, suggesting a mechanistic role for the hormone in the reduction of flavokinase activity.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Sep
pubmed:issn
0007-1145
pubmed:author
pubmed:issnType
Print
pubmed:volume
76
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
453-62
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
1996
pubmed:articleTitle
Flavin metabolism during respiratory infection in mice.
pubmed:affiliation
Department of Biochemistry, National Institute of Nutrition, Jamai Osmania, Hyderabad, India.
pubmed:publicationType
Journal Article