OBJECTIVETo test the possibility that certain efficient substrates for lipoxygenase (LOX) produce shuttle oxidants that stimulate the generation of reactive oxygen species from other chemicals.

METHODSMetabolic interactions were conducted in vitro between chlorpromazine (BZ) or other phenothiazines and benzidine or other xenobiotics mediated by soybean lipoxygenase (SLO) or purified human term placental lipoxygenase (HTPLO) in the presence of hydrogen peroxide, and the rates of xenobiotics oxidation were measured by spectroscopic analysis.

RESULTSChlorpromazine cation radical (CPZ(*+)) generated by lipoxygenase triggered a rapid oxidation of benzidine to benzidine diimine cation. Under the experimental conditions used, the metabolic interaction resulted in a 42-fold greater stimulation than BZ alone in the rate of BZ oxidation. The magnitude of stimulation of benzidine oxidation exhibited a dependence on the pH of the reaction medium, amount of the enzyme, and concentration of chlorpromazine, BZ, and hydrogen peroxide. A number of other phenothiazines were also found to stimulate BZ oxidation, albeit to a lesser degree. Chlorpromazine cation radical stimulated the oxidation of all six other xenobiotics tested. The highest stimulation (94-fold) was noted in the oxidation of tetramethyl phenylenediamine to Wursters blue radical, while the lowest stimulatory response (2-fold) was observed in guaiacol. Preliminary data showed that purified HTPLO also displayed a similar stimulatory response to benzidine oxidation in the presence of chlorpromazine.

CONCLUSIONBoth soybean lipoxygenase and purified human term placental lipoxygenase can mediate stimulatory response to the oxidation of benzidine and other xenobiotics in the presence of phenothiazines.

Benzidines ; metabolism ; Chlorpromazine ; chemistry ; Drug Interactions ; Female ; Humans ; Lipoxygenase ; isolation & purification ; pharmacology ; Oxidation-Reduction ; drug effects ; Phenothiazines ; pharmacology ; Placenta ; enzymology ; Pregnancy ; Xenobiotics ; metabolism

The effects of ethyl alcohol and pig serum administration on the development of preneoplastic hepatic enzyme-altered foci were examined in an in vivo mid-term assay system. Rats were initially given a single dose (200 mg/Kg) intraperitoneal injection of diethylnitrosamine (DEN). Two weeks later, treatment was started with 10% ethanol + 10% sucrose solution, 10% sucrose solution, or tap water as drinking water for 6 weeks with or without intraperitoneal injection of porcine serum twice a week. All rats were subjected to a two-thirds partial hepatectomy at week 3. The modification potentials were evaluated by comparing the number and area per cm2 of glutathione S-transferase placental form-positive (GST-P+) foci in the liver of each group. As a result, ethanol significantly enhanced the development of GST-P+ foci. Unfortunately, the porcine serum injection produced no hepatic fibrosis and no significant alteration in GST-P+ foci.
Animals ; Diethylnitrosamine/*toxicity ; Ethanol/*pharmacology ; Glutathione Transferase/*metabolism ; Immune Sera/pharmacology ; Liver Cirrhosis, Alcoholic/enzymology ; Male ; Placenta/drug effects/*enzymology ; Precancerous Conditions/*chemically induced/enzymology ; Rats ; Rats, Inbred F344 ; Survival Rate ; Swine

Axl encodes the tyrosine-protein kinase receptor, participating in the proliferation and migration of many cells. This study examined the role of Axl in functions of endothelial progenitor cells (EPCs). Axl was detected by RT-PCR and Western blotting in both placentas and EPCs from normal pregnancy and preeclampsia patients. The Axl inhibitor, BMS777-607, was used to inhibit the Axl signalling pathway in EPCs. Cell proliferation, differentiation, migration and adhesion were measured by CCK-8 assay, cell differentiation assay, Transwell assay, and cell adhesion assay, respectively. Results showed the expression levels of Axl mRNA and protein were significantly higher in both placentas and EPCs from preeclampsia patients than from normal pregnancy (P<0.05). After treatment with BMS777-607, proliferation, differentiation, migration and adhesion capability of EPCs were all significantly decreased. Our study suggests Axl may play a role in the function of EPCs, thereby involving in the pathogenesis of preeclampsia.
Adult ; Aminopyridines ; pharmacology ; Blood Pressure ; Case-Control Studies ; Cell Adhesion ; drug effects ; Cell Differentiation ; drug effects ; Cell Movement ; drug effects ; Cell Proliferation ; drug effects ; Female ; Fetal Blood ; cytology ; enzymology ; Gene Expression Regulation ; Gestational Age ; Human Umbilical Vein Endothelial Cells ; drug effects ; enzymology ; pathology ; Humans ; Placenta ; metabolism ; physiopathology ; Pre-Eclampsia ; blood ; genetics ; physiopathology ; Pregnancy ; Primary Cell Culture ; Protein Kinase Inhibitors ; pharmacology ; Proto-Oncogene Proteins ; antagonists & inhibitors ; genetics ; metabolism ; Pyridones ; pharmacology ; RNA, Messenger ; antagonists & inhibitors ; genetics ; metabolism ; Receptor Protein-Tyrosine Kinases ; antagonists & inhibitors ; genetics ; metabolism ; Stem Cells ; drug effects ; enzymology ; pathology