Abstract
BACKGROUND: Catabolism is a serious problem in patients with active inflammation. The tissue nitrogen (N) depletion is related to increased hepatic capacity for elimination of N via conversion of amino-N into urea-N. This is caused by the inflammatory process, but the mediators responsible are unknown. Tumor necrosis factor-alpha (TNF-alpha) plays a key role in inflammation, and we hypothesized that TNF-alpha up-regulates urea synthesis.
METHODS: We examined the in vivo capacity of urea-N synthesis (CUNS) and mRNA levels of urea cycle enzyme genes 3 h after TNF-alpha injection in rats. Circulating concentrations of glucagon, corticosterone, insulin, glucose, cytokines and acute phase proteins and their liver tissue gene expressions were measured.
RESULTS: TNF-alpha increased CUNS by 40% (p=0.03) despite decreased urea-cycle enzyme gene expression. TNF-alpha increased interleukin 6 (IL-6) (p < 0.001); circulating acute phase proteins were unchanged.
CONCLUSION: TNF-alpha in rats caused an acute up-regulation of the in vivo capacity of urea synthesis which may promote loss of nitrogen from the body and catabolism. The results indicate that TNF-alpha has a post-transcriptional effect on regulation of urea synthesis that is independent of the acute phase protein synthesis. Effects of IL-6 may be involved.
| Originalsprog | Engelsk |
|---|---|
| Tidsskrift | Scandinavian Journal of Clinical and Laboratory Investigation |
| Vol/bind | 70 |
| Udgave nummer | 3 |
| Sider (fra-til) | 151-7 |
| Antal sider | 7 |
| ISSN | 0036-5513 |
| DOI | |
| Status | Udgivet - 19 apr. 2010 |
| Udgivet eksternt | Ja |
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