Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
2
pubmed:dateCreated
1990-7-2
pubmed:abstractText
The lysosomal proteolytic capacity of mouse brown adipose tissue (BAT) and its role during fasting were evaluated. The specific activities of acid phosphatase and cathepsins B, D, H, and L were measured in BAT of mice acclimated at 33, 21, and 4 degrees C and in BAT undergoing different rates of protein loss during a 24- to 48-h fast. The specific activities of lysosomal proteases in BAT did not vary with the acclimation status of the animals. Mice acclimated at 33 degrees C showed no significant atrophy of BAT after a fast. In mice kept at 21 degrees C, protein loss from BAT was observed after a fast without change in tissue DNA content. Protein loss from BAT was partially reduced by injection of the acidotropic agent chloroquine. Furthermore, tyrosine release from BAT during fasting was also reduced by injections of chloroquine or leupeptin, a thiol-protease inhibitor. Tyrosine release from BAT was maximum within 24 h and returned to prefast values by 36 h, suggesting rapid activation followed by inhibition of the tissue proteolytic activity. However, there was no change in acid protease specific activities, suggesting that these enzymes were not limiting for protein degradation. When cold-acclimated mice were fasted at 21 degrees C, BAT protein loss was markedly enhanced and increases in cathepsin D and L activities were observed, but there was no change in cathepsin B and H and acid phosphatase specific activities. These results indicate that BAT contains an important lysosomal proteolytic pathway that is involved in the rapid reduction of the tissue thermogenic capacity during a fast.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Feb
pubmed:issn
0829-8211
pubmed:author
pubmed:issnType
Print
pubmed:volume
68
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
441-7
pubmed:dateRevised
2009-11-19
pubmed:meshHeading
pubmed:year
1990
pubmed:articleTitle
Role of acid proteases in brown adipose tissue atrophy caused by fasting in mice.
pubmed:affiliation
Department of Physiology, College of Medicine, University of Saskatchewan, Saskatoon, Canada.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't