Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:4.1.1.32 (phosphoenolpyruvate carboxykinase)
 4,204 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The accelerated mobilization of peripheral protein and subsequent increased gluconeogenesis are regarded as mechanisms of cancer cachexia. To determine the relation of gluconeogenesis to different degrees of tumor burden and subsequent tumor removal in the fed and fasted states, we examined the activity and mRNA levels of the key regulatory enzyme for gluconeogenesis: phosphoenolpyruvate carboxykinase (PEPck) in the liver of Fischer rats with a transplanted methylcholanthrene-induced sarcoma. PEPck activity in liver cytosol, after a 24-hour fast, was significantly higher in the tumor-bearing rats than in their pair-fed controls. The increase in enzyme activity was clearly evident at 8% tumor burden and correlated positively with the degree of tumor burden (r = 0.85, p less than 0.01). Removal of the tumor produced a complete reversal of PEPck activity 10 days after excision. Regular feeding also abolished this increased enzyme activity. A similar trend was seen in the mitochondria. PEPck mRNA levels of rats with greater than 11% tumor burden in the fed state were decreased more than those of controls. PEPck mRNA levels were equally elevated in tumor bearers and controls in the 24-hour-fasted state. These results suggest that tumor-bearing simulates the fasted state associated with hypoglycemia, which in turn triggers induction of the gluconeogenic enzyme, PEPck.
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PMID:The reversal of increased gluconeogenesis in the tumor-bearing rat by tumor removal and food intake. 276 39

This study was conducted to investigate the role of tumor necrosis factor-alpha (TNF-alpha) and interleukin-2 (IL-2) in inducing cancer cachexia, and the results were compared with those obtained from our previous study on Fisher 344 rats with methylcholanthrene-induced sarcoma. Three groups of male Fisher 344 rats received one of the following regimens: 4 x 10(4) IU of human recombinant TNF-alpha per rat per day subcutaneously (sc) for 5 consecutive days (n = 5), 3.5 x 10(5) U human recombinant IL-2 per rat per day sc for 14 consecutive days (n = 5), or normal saline (n = 5). The activities of both phosphoenolpyruvate carboxykinase (PEPCK) and malic enzyme (ME) were increased slightly in the IL-2 group. Furthermore, LPL activity was significantly increased in the adipose tissue of the TNF group and in the cardiac muscle of the IL-2 group, but not in that of the TNF group. These results show that there is a significant difference between the metabolic alterations seen in the tumor-bearing state and those induced by either TNF-alpha or IL-2 alone. Thus, it is unlikely that IL-2 or TNF-alpha is the sole mediator of cancer cachexia in this tumor and rat model.
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PMID:The possible role of TNF-alpha and IL-2 in inducing tumor-associated metabolic alterations. 868 Jan 18