Selective Induction of Human Hepatic Cytochromes P450 2B6 and 3A4 by Metamizole

The pyrazolone drug metamizole is a widely used analgesic. Analysis of liver microsomes from patients treated with metamizole revealed selectively higher expression of cytochromes P450, CYP2B6 and CYP3A4 (3.8- and 2.8-fold, respectively), and 2.9-fold higher bupropion hydroxylase activity compared with untreated subjects. Further investigation of metamizole and various derivatives on different potential target genes in human primary hepatocytes demonstrated time- and concentration-dependent induction by metamizole of CYP2B6 (7.8- and 3.1-fold for mRNA and protein, respectively, at 100 muM) and CYP3A4 (2.4- and 2.9-fold, respectively), whereas other genes (CYP2C9, CYP2C19, CYP2D6, NADPH:cytochrome P450 reductase, ABCB1, constitutive androstane receptor (CAR), pregnane X receptor (PXR)) were not substantially altered. Using reporter gene assays, we show that metamizole is not acting as a direct ligand to either PXR or CAR, suggesting a phenobarbital-like mechanism of induction. These data warrant further studies to elucidate the drug-interaction potential of metamizole, especially in patients with long-term treatment.

Changes in Serum Levels of Growth Factors in Healthy Individuals After Living Related Liver Donation

INTRODUCTION

To obtain better insight into the kinetics of hepatic growth factors following partial hepatectomy for living related liver donation, we investigated the postoperative changes in serum levels of hepatocyte growth factor (HGF), epidermal growth factor (EGF), vascular epidermal growth factor (VEGF), and transforming growth factor-alpha (TGF-alpha).

PATIENTS AND METHODS

Eighteen healthy donors undergoing right hepatectomy for living related donation were enrolled in this study. Serum levels of HGF, EGF, VEGF, and TGF-alpha were measured using enzyme-linked immunosorbent assay kits before surgery, at 2 hours after resection, and daily during 5 days postoperatively.

RESULTS

Mean preoperative HGF serum levels in healthy adults were 778 +/- 64 pg/mL. Within 2 hours after operation, they significantly increased to 9608 +/- 3111 pg/mL afterward decreasing to 2726 +/- 241 at day 1 and 2283 +/- 250 pg/mL at day 2. Hereafter HGF serum levels stabilized at increased levels until day 5 (2109 +/- 138, 2047 +/- 219, 2283 +/- 336 pg/mL, respectively). At all time points, the differences between pre- and postoperative HGF levels were significant (P < .01). In contrast, VEGF and EGF serum levels showed no significant differences between pre- and postoperative levels at all time points. TGF-alpha was not detected using a commercially available test with a detection limit of 10 ng/mL, suggesting only low TGF-alpha serum levels following liver resection.

CONCLUSION

Significantly increased HGF serum levels after hepatectomy demonstrate its crucial role among the other investigated growth factors in regeneration of the remnant liver tissue during the early period after the operation.