Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.4.24.3 (collagenase)
 18,340 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Troglitazone (TRO) is an insulin sensitizer used in the treatment of type II diabetes. TRO is known to increase the activity of cytochrome P-450 (CYP) 3A in vivo. We have investigated the effect of TRO on CYP3A protein content and the activity of CYP3A (as measured by the formation of 6beta-hydroxytestosterone formation) in primary cultures of human hepatocytes in comparison with rifampicin (RIF). Hepatocytes were isolated from four human livers by perfusion with collagenase, plated on collagen-coated plates, and maintained in William's E medium. After 48 h in culture, cells were exposed to RIF (10 microM) or TRO (0-50 microM) twice, each over a period of 24 h, and the activity of CYP3A was measured. TRO increased the activity of CYP3A in a concentration-dependent manner, reaching a maximal response at 5 microM. Pretreatment of the hepatocytes with 10 microM TRO or 10 microM RIF resulted in a 4- to 15-fold increase in the activity of CYP3A. Maximum increase in CYP3A protein was observed at 5 microM TRO. There was a significant correlation (R(2) = 0.89) between the content of immunoreactive CYP3A protein in the hepatocytes and the rate of formation of 6beta-hydroxytestosterone. These results indicate that TRO is a potent inducer of CYP3A and is similar to RIF in inducing CYP3A in human hepatocytes. At concentrations of 25 microM and above, TRO was toxic to the cells, as determined by a decrease in the activity of CYP3A, a reduction in the amount of immunoreactive protein, and changes in the morphology of the cells.
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PMID:Troglitazone increases cytochrome P-450 3A protein and activity in primary cultures of human hepatocytes. 1049 47

Increased dietary fat intake in general, and saturated fat specifically, will lead to the impairment of insulin action. The aim of this study was to find out the changes in hepatic glucose output in dependence of fat diet and a possible direct action of insulin and trogitazone in hepatocytes. Hepatocytes were isolated by a collagenase perfusion technique and cultured for 24 h in M 199 serum-free medium. The glucose production in hepatocytes isolated from rats on high fat diet (unsaturated fat) was 79% higher compared to control and even 139% higher than in rats on high-fat diet (saturated fat). Troglitazone significantly decreased the glucose production in hepatocytes obtained from rats on unsaturated fat diet. The troglitazone in presence of insulin totally normalized glucose production but also only in hepatocytes obtained from rats on unsaturated-fat diet. The troglitazone showed an insulinomimetic as well as insulin-sensitizing effect but only in rats on unsaturated-fat diet.
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PMID:Effects of troglitazone and insulin on glucose production in cultured hepatocytes isolated from rats on high fat diet. 1566 94