OBJECTIVEIn order to explore the pathway of dealkylation of pesticides other than cytochrome P450 monocoxygenases, lipoxygenase (LOX)-mediated demethylation of aminocarb and some other pesticides were measured.

METHODFormaldehyde generated in the reaction was estimated by Nash reaction to express the rate of demethylation of pesticides mediated by soy lipoxygenase (SLO).

RESULTSN-demethylation of aminocarb mediated by SLO was found to depend on the incubation time, concentration of the enzyme, concentration of aminocarb and hydrogen peroxide. Under optimal conditions, Vmax value of 18 nmol of formaldehyde.min-1.nmol-1 of lipoxygenase was observed. The reaction exhibited Km values of 3.4 mmol/L for aminocarb and 235 mumol/L for hydrogen peroxide. A strong inhibition of the reaction by nordihydroguaiaretic acid, gossypol, and phenidone clearly implicated the lipoxygenase involvement as the protein catalyst. A significant decline in the formaldehyde accumulation in the presence of either reduced glutathione or dithiothreitol suggested generation of a free radical species as an initial oxidation intermediate during the demethylation of aminocarb by SLO. The inhibition of formaldehyde generation by butylated hydroxyanisole(BHT) and butylated hydroxy toluene(BHA) further supported this contention. In addition to aminocarb, seven other pesticides were also found to undergo N-demethylation, albeit at relatively low rates.

CONCLUSIONCertain pesticides may oxidatively undergo dealkylation via the lipoxygenase pathway in animals and plants.

Butylated Hydroxyanisole ; pharmacology ; Butylated Hydroxytoluene ; pharmacology ; Dealkylation ; Free Radicals ; Lipoxygenase ; physiology ; Pesticides ; metabolism ; Phenylcarbamates ; metabolism ; Soybeans ; enzymology

Effects of feeding 2(3)-tert-butyl 4-hydroxyanisole (BHA) and 3, 5-di-tert-butyl 4-hydroxytoluene (BHT) on the rates of mixed function oxidation and conjugation enzyme reactions have been determined using isolated hepatic microsomal fractions and isolated perfused livers of mice. The treatments with either of the antioxidants have increased the rates of O-demethylation for p-nitroanisole and of O-deethylation for 7-ethoxycoumarin up to 2-fold, both in microsomes and in perfused liver. Analysis of the perfusate showed that the increased amounts of p-nitrophenol and 7-hydroxycoumarin produced by the elevated mixed-function oxidase activities were reflected by the increase in the amounts of glucuronide conjugates and not in the increase for the amounts of the sulfate ester conjugates. Comparison of results also indicated that in the perfused liver, the maximal rate of metabolite conjugation is limited by the maximal rates of the initial mixed function oxidase activities.
Alkylation ; Animal ; Anisoles/metabolism ; Anisoles/pharmacology* ; Butylated Hydroxyanisole/administration & dosage ; Butylated Hydroxyanisole/pharmacology* ; Butylated Hydroxytoluene/administration & dosage ; Butylated Hydroxytoluene/analogs & derivatives* ; Butylated Hydroxytoluene/pharmacology ; Comparative Study ; Coumarins/metabolism ; Female ; Glucuronosyltransferase/metabolism ; Liver/metabolism* ; Mice ; Microsomes, Liver/enzymology ; Microsomes, Liver/metabolism* ; Mixed Function Oxygenases/metabolism ; Oxidation-Reduction ; Perfusion ; Support, U.S. Gov't, P.H.S.

The inhibitory effect of selenium, vitamin E, and BHA on DMBA-induced mammary tumorigenesis in rats was investigated. Dietary vitamin E (200 IU/Kg diet) alone could not reduce the tumor incidence at 25 weeks after DMBA administration (10mg DMBA/rat) when selenium was deficient. Selenium supplementation (2ppm in drinking water) to rats fed a practical diet (0.17 ppm Se) reduced the tumor incidence to 14.3% from 75% at 27 weeks after DMBA administration. Dietary supplementation of BHA (0.75%) also reduced the incidence of DMBA-induced mammary tumor to 42.9% at 27 weeks after DMBA-treatment. Rats fed a diet deficient in both selenium and vitamin E contained significantly lower glutathione peroxidase activity and higher malondialdehyde in muscle. However, supplementation of selenium or BHA to the rats fed a practical diet did not alter the malondialdehyde content and glutathione peroxidase activities in muscle, skin and mammary gland. Dietary selenium increased the tissue selenium level. DMBA-induced mammary tumorigenesis was reduced by antioxidants tested but the anticarcinogenic effect of selenium or BHA seems to be independent of glutathione peroxi-dase activity.
9,10-Dimethyl-1,2-benzanthracene ; Animal ; Antioxidants/pharmacology* ; Butylated Hydroxyanisole/pharmacology ; Female ; Mammary Neoplasms, Experimental/pathology* ; Rats ; Selenium/pharmacology ; Vitamin E/pharmacology

AIMTo establish model of differentiation of fetal liver stem cells induced by beta-ME + BHA into neural cells in vitro;

METHODSCD34+ cells from naturally aborted human fetal liver were isolated with MACS Kit, and cultured in Dulbecco's modified Eagle's medium (DMEM) supplemented with 10% fetal bovine serum (FBS). After confluent more than 80%, the 5 passage cells were induced by 10(-3) mol/L beta-mercaptoethanol (beta-ME) and 2 x 10(-4) mol/L BHA for 24 hours, and washed with PBS, and then incubated in serum-free medium for 5 hours to 5 days. The characteristics of treated cells were assayed by immunocytochemistry staining analysis.

RESULTSCells treated by beta-ME+ BHA exhibited neuronal phenotype, and expressed neuronal specific proteins such as nestin, NeuN, TrnJ-1, and NF-M, which were not found in control cells. Statistic analysis showed that 81% cells were NeuN-positive, 75% cells TuJ-1-positive, 47% cells NF-M-positive, 90% cells NSE-positive.

CONCLUSIONbeta-ME + BHA can induce human fetal liver CD34+ cells to produce neuronal specific antigens and proteins in vitro and become neuronal cells. CD34+ cells from human fetal liver possess potentials of differentiation into neural cells.

Antigens, CD34 ; Butylated Hydroxyanisole ; pharmacology ; Cell Differentiation ; drug effects ; Cells, Cultured ; Hematopoietic Stem Cells ; cytology ; drug effects ; Humans ; Liver ; cytology ; embryology ; Mercaptoethanol ; pharmacology ; Neurons ; cytology

AIMTo study the mechanism of butylated hydroxyanisole-induced neural differentiation of fetal liver cells in vitro.

METHODS14.5-day-old mouse fetal liver-derived cells were cultured, and were induced by 200 micromol/L butylated hydroxyanisole (BHA) combined with PI3K inhibitor LY294002 (20 micromol/L), and then were incubated in serum-free medium. Expression of genes in treated or untreated cells were assayed by Western blotting or RT-PCR.

RESULTSThere was low level of neurofilament-L (NF-L) and brain factor-1 (BF-1) but no neurofilament-H (NF-H) and tyrosine hydroxylase (TH) in fetal liver cells. BHA promoted significantly expression of neuron-specific NF-L, NF-H, BF-1, and TH in fetal liver cells. NF-L mRNA increased 5.8 fold, NF-H mRNA 8.0 fold, BF-1 mRNA 2.68 fold, and TH mRNA 30 fold, respectively (all P < 0.01 vs untreated cells). NF-L protein increased 11.29 fold, NF-H 5.5 fold, BF-1 2.53 fold, TH 4.76 fold. Moreover, expression of these BHA-induced genes were inhibited by PI3K inhibitor LY294002.

CONCLUSIONBHA induced neural differentiation of fetal liver cells through PI3K.

Animals ; Butylated Hydroxyanisole ; pharmacology ; Cells, Cultured ; Embryo, Mammalian ; cytology ; Hepatocytes ; drug effects ; metabolism ; Mice ; Mice, Inbred C57BL ; Nerve Tissue Proteins ; biosynthesis ; genetics ; Phosphatidylinositol 3-Kinases ; metabolism

Butylated hydroxyanisole (BHA) is a synthetic phenolic compound consisting of a mixture of two isomeric organic compounds: 2-tert-butyl-4-hydroxyanisole and 3-tert-butyl-4-hydroxyanisole. We examined the effect of BHA against hydrogen peroxide (H2O2)-induced apoptosis in primary cultured mouse hepatocytes. Cell viability was significantly decreased by H2O2 in a dose-dependent manner. Additionally, H2O2 treatment increased Bax, decreased Bcl-2, and promoted PARP-1 cleavage in a dose-dependent manner. Pretreatment with BHA before exposure to H2O2 significantly attenuated the H2O2-induced decrease of cell viability. H2O2 exposure resulted in an increase of intracellular reactive oxygen species (ROS) generation that was significantly inhibited by pretreatment with BHA or N-acetyl-cysteine (NAC, an ROS scavenger). H2O2-induced decrease of cell viability was also attenuated by pretreatment with BHA and NAC. Furthermore, H2O2-induced increase of Bax, decrease of Bcl-2, and PARP-1 cleavage was also inhibited by BHA. Taken together, results of this investigation demonstrated that BHA protects primary cultured mouse hepatocytes against H2O2-induced apoptosis by inhibiting ROS generation.
Animals ; Apoptosis/*drug effects ; Butylated Hydroxyanisole/chemistry/*pharmacology ; Cell Survival/drug effects ; Cells, Cultured ; Hepatocytes/*drug effects ; Hydrogen Peroxide/*toxicity ; Male ; Mice ; Mice, Inbred ICR ; Molecular Structure

An experiment was conducted in order to investigate the effect of p-dimethylaminoazobenzene (DAB) and 2(3)-tert-butyl-4-hydroxyanisole (BHA) on the lipid peroxidation and peroxide-destroying enzyme system in the rat liver. Dietary supplementation of DAB (0.06%) for three weeks caused the elevation of glutathione-S-transferase activity by 60% and glutathione reductase by 50%, but it decreased glutathione peroxidase and catalase activities significantly. Dietary supplementation of BHA (0.75%) also increased glutatione-S-transferase activity in the liver by 2 folds, and it counteracts DAB effect on the glutathione peroxidase and catalase activities. There was a marked increase in malon-dialdehyde content in the postnuclear fraction of liver by the treatment of DAB, but the addition of BHA lowered the malondialdehyde content to almost the control level. The protective effect of BHA on the lipid peroxidation induced by DAB administration at the enzyme level seems to be due to the induction of glutathione-S-transferase and the protection of glutathione peroxidase and catalase activities from being lowered by DAB administration.
Animal ; Anisoles/pharmacology* ; Butylated Hydroxyanisole/pharmacology* ; Glutathione Peroxidase/analysis* ; Glutathione Reductase/analysis* ; Glutathione Transferase/analysis* ; Lipid Peroxides/metabolism* ; Liver/drug effects* ; Liver/metabolism ; Male ; Peroxidases/analysis* ; Rats ; p-Dimethylaminoazobenzene/pharmacology*