Dissociation of sympathetic and thermogenic activity in brown fat of XXXX .

@entity28 @entity7298 @entity1184 @entity3006 @entity1017 @entity329 @entity1063
@entity329 ( @entity329 ) were fed a high-fat (HF) diet for up to 16 wk. Sympathetic and thermogenic activities in their brown adipose tissue (BAT) were assessed by measuring @entity1063 content and turnover and mitochondrial @entity3006 binding and cytochrome c oxidase activity. Chronic ingestion of the HF diet resulted in significant increases in carcass lipid and interscapular BAT wet weight by the end of the second week. HF-fed hamsters were slightly hyperphagic during the first 2 wk of HF feeding only. Significant @entity1017 persisted beyond the period of @entity7298 . @entity1184 of interscapular BAT after 16 wk on the HF diet was accompanied by increases in protein and DNA content, indicating growth of functional tissue. @entity1063 turnover and content in BAT were decreased throughout the entire period of HF feeding, regardless of changes in caloric intake or body weight. Mitochondrial cytochrome c oxidase activity and @entity3006 binding were increased after 16 wk on the HF diet, a time when the HF-fed animals were @entity28 but not hyperphagic. These results demonstrate a dissociation of BAT thermogenesis from sympathetic activity in the tissue. It appears that sympathetic nervous system activity in BAT was suppressed by the HF diet, whereas thermogenic activity of the tissue was activated when the hamsters became @entity28 .
