A wide-spectrum initiation model was investigated in mice. Sequential treatments with diethylnitrosamine, urethane and N-methylnitrosourea, with or without a promoter, phenobarbital, resulted in tumor formation in the lungs in 85-90% of animals, but did not produce any tumorous lesions in other organs. The lung tumors were adenomas and the mean number of adenomas was 2.2-2.6 per mouse. Phenobarbital combination had no additive effect on lung tumor incidence and multiplicity. Splenic NK cell activity showed inconsistent increment in the carcinogen plus phenobarbital-treated group during the experiment (P less than 0.05).
*Adenoma/chemically induced/immunology ; Animals ; Diethylnitrosamine/pharmacology ; Female ; *Killer Cells, Natural/drug effects ; *Lung Neoplasms/chemically induced/immunology ; Methylnitrosourea/pharmacology ; Mice ; Phenobarbital/pharmacology ; Random Allocation ; Urethane/pharmacology

OBJECTIVETo study the stereoselectivity of R-(+) and S-(-)-propranolol glucuronidation and metabolic interaction between R(+)- and S-(-)-propranolol.

METHODSA RP-HPLC analytical method was developed for determination of R-(+)-and S-(-)-propranolol glucuronide (PG) incubated with rat hepatic microsome induced with phenobarbital (PB). The method was applied to investigate the stereoselectivity metabolism of racemic propranolol glucuronidation in vitro.

RESULTIn control and PB group, the concentration of R-(+)-PG produced at different substrates was higher than that of S-(-)-PG. Compared with the control, the V(max) and Cl(int) for R(+)-and S-(-)-propranolol increased significantly the K(m) for R(+)-propranolol was elevated, while that for S-(-) propranolol was decreased.

CONCLUSIONThere is a stereoselectivity in glucuronidation of propranolol in rat hepatic microsome induced with PB and R-(+)-propranolol is preferred. Metabolic interaction between R-(+)-and S-(-)-propranolol exists with a concentration-dependent mode.

Animals ; Enzyme Induction ; Microsomes, Liver ; enzymology ; Phenobarbital ; pharmacology ; Propranolol ; analogs & derivatives ; metabolism ; Rats ; Rats, Sprague-Dawley ; Stereoisomerism

OBJECTIVESBy culturing primary early (8 to 12-weeks-old) human fetal hepatocytes with different conditions, to study the status of cell susceptibility to HBV.

METHODSDuring primary culture of 10-weeks-old human fetal hepatocytes with serum-free medium adding different differentiation-induced ingredients, to inoculate cell with HBV at certain time. Cell shape, function and markers of HBV infection are measured.

RESULTS6 days after seeding, markers of mature hepatocytes are observed in cells cultured with 2.5mmol/L phenobarbital sodium, and these cells show susceptibility to HBV. Other ingredients cannot render hepatocytes susceptible to HBV.

CONCLUSIONPhenobarbital sodium induces differentiation and susceptibility to HBV in primary culture of early human fetal hepatocytes.

Cell Differentiation ; drug effects ; Cells, Cultured ; Female ; Fetus ; virology ; Hepatitis B virus ; growth & development ; Hepatocytes ; cytology ; physiology ; virology ; Humans ; Phenobarbital ; pharmacology ; Pregnancy ; Pregnancy Trimester, First

The present work was to study induction of cytochrome P450 (CYP)3A and CYP2H1 gene by reverse transcriptase polymerase chain reaction (RT-PCR) and quantitative RTPCR in Bantam, Bantamized White Leghorn and White Leghorn chicks. Out of 18 chicks total 3 from each group (Bantam, Bantamized White Leghorn and White Leghorn) were treated intraperitoneal with phenobarbital at the dose rate of 12 mg/100 g (body weight) while the control group was treated with the saline. Total RNA was extracted from the liver samples using Tri Reagent based method. First strand cDNA was synthesized using one step RT-PCR kit. The PCR was performed and the product was subjected to agarose gel electrophoresis. Quantitative RT-PCR was conducted to quantify gene expression level of CYP3A and CYP2H1 genes. Relative expression ratio of CYP3A and CYP2H1 genes was calculated using relative expression software tool (REST). It was found that CYP3A is up regulated by factor of 1.34, 14.51 and 1.00 in Bantam, Bantamized White Leghorn and White Leghorn chicks, respectively. In Bantam and Bantamized White Leghorn chicks CYP2H1 gene was up regulated by factor 1.50 and 80.87, respectively but down regulated by a factor of 1.97 in White Leghorn chicks. The PCR efficiency ranged from 1.30 to 1.70, 0.86 to 1.70 and 0.91 to 1.58 for CYP3A, CYP2H1 and beta-actin, respectively in Bantam, Bantamized White Leghorn and White Leghorn chicks.
Animals ; Chickens/*metabolism ; Cytochrome P-450 CYP3A/*biosynthesis/genetics ; Cytochrome P-450 Enzyme System/*biosynthesis/genetics ; Gene Expression Regulation/drug effects ; Phenobarbital/*pharmacology ; Reverse Transcriptase Polymerase Chain Reaction

AIMTo investigate the antiepileptic effect of dizocilpine (MK-801) on amygdala kindling models in rats and the effects of its combination with general antiepileptic drugs.

METHODSTo establish amygdala kindling models in rats and observe the effect of dizocilpine on kindling models and its combination with general antiepileptic drugs (phenobarbital, valproate and nicardipine) at ineffective dose. The influence of dizocilpine on convulsions induced by semicarbazide (SCZ) in mice were also observed.

RESULTSDizocilpine (0.1-0.25 mg.kg-1, i.p.) was shown to dose-dependently inhibit amygdala kindled seizure, shorten the after discharge duration (ADD) and reduce the Racine's stage (P < 0.01). The combination of dizocilpine with phenobarbital, valproate, nicardipine at ineffective dose shortened ADD or reduced Racine's stages (P < 0.01). Dizocilpine (0.1-0.25 mg.kg-1, i.p.) significantly prolonged the latency and reduced the rate of convulsions and death in mice.

CONCLUSIONDizocilpine inhibits the seizure of the amygdala kindling and improve the antiepileptic activity of phenobarbital, valproate and nicardipine, indicating that these combination may provide a new approach for treating epilepsy.

Amygdala ; drug effects ; physiopathology ; Animals ; Anticonvulsants ; pharmacology ; therapeutic use ; Dizocilpine Maleate ; pharmacology ; therapeutic use ; Electric Stimulation ; Epilepsy ; chemically induced ; drug therapy ; Female ; Kindling, Neurologic ; drug effects ; Male ; Mice ; Nicardipine ; pharmacology ; Phenobarbital ; pharmacology ; Random Allocation ; Rats ; Rats, Wistar ; Semicarbazides ; Valproic Acid ; pharmacology

The nuclear receptors, steroid and xenobiotic receptor (SXR) and constitutive androstane receptor (CAR) play important functions in mediating lipid and drug metabolism in the liver. The present study demonstrates modulatory actions of estrogen in transactivations of SXR-mediated liver X receptor response element (LXRE) and CAR-mediated phenobarbital response element (PBRU). When human estrogen receptor (hERalpha) and SXR were exogenously expressed, treatment with either rifampicin or corticosterone promoted significantly the SXR-mediated transactivation of LXRE reporter gene in HepG2. However, combined treatment with estrogen plus either rifampicin or corticosterone resulted in less than 50% of the mean values of the transactivation by rifampicin or corticosterone alone. Thus, it is suggested that estrogen may repress the SXR-mediated transactivation of LXRE via functional cross-talk between ER and SXR. The CAR-mediated transactivation of PBRU was stimulated by hERalpha in the absence of estrogen. However, the potentiation by CAR agonist, TCPOBOP, was significantly repressed by moxestrol in the presence of ER. Thus, ER may play both stimulatory and inhibitory roles in modulating CAR-mediated transactivation of PBRU depending on the presence of their ligands. In summary, this study demonstrates that estrogen modulates transcriptional activity of SXR and CAR in mediating transactivation of LXRE and PBRU, respectively, of the nuclear receptor target genes through functional cross-talk between ER and the corresponding nuclear receptors.
Corticosterone/pharmacology ; Estrogens/*metabolism ; Ethinyl Estradiol/analogs & derivatives/pharmacology ; Hep G2 Cells ; Humans ; Liver/*metabolism ; Orphan Nuclear Receptors/metabolism ; Phenobarbital/metabolism ; Pyridines/pharmacology ; Receptor Cross-Talk ; Receptors, Cytoplasmic and Nuclear/agonists/*metabolism ; Receptors, Steroid/*metabolism ; Response Elements ; Rifampin/pharmacology ; Transcriptional Activation/*drug effects/physiology

Adult ; Cell Differentiation ; drug effects ; Cells, Cultured ; DNA, Viral ; analysis ; Female ; Fetus ; virology ; Hepatitis B virus ; genetics ; growth & development ; isolation & purification ; Hepatocytes ; cytology ; physiology ; virology ; Humans ; Nucleic Acid Hybridization ; methods ; Phenobarbital ; pharmacology ; Pregnancy ; Pregnancy Trimester, First

A 35-yr-old woman carrying a 17-week-old fetus presented with right hydronephrosis and a single umbilical artery. Karyotyping was normal and targeted ultrasonography showed an otherwise normal fetus. After 28 weeks of gestation, the mother felt rapid, repetitive fetal movement and an ultrasound at 30 weeks of gestation revealed tonic clonic movements of the fetal trunk and extremities. At 36 weeks of gestation, an emergency repeat Cesarean section was performed because of a premature rupture of the membranes and a male infant weighing 4,295 gm was delivered. After birth, the infant continued to have movements suggestive of a generalized tonic clonic seizure. Brain computed tomography and magnetic resonance imaging revealed normal structures and an electroencephalography showed generalized suppression. Treatment with phenobarbital resulted in substantial improvement in the number of seizure episodes, however fine seizure-like movement continued in both of the hands, feet and in the tongue until the five-month follow-up. This is the first Korean report of a fetal seizure being diagnosed during the prenatal period.
Female ; Fetal Diseases/*diagnosis/ultrasonography ; Humans ; Infant, Newborn ; Karyotyping ; Magnetic Resonance Imaging/methods ; Male ; Phenobarbital/pharmacology ; Pregnancy ; Prenatal Diagnosis/*methods ; Seizures/*diagnosis ; Tomography, X-Ray Computed/methods ; Ultrasonography, Prenatal/*methods

Synaptic vesicle protein 2A (SV2A) involvement has been reported in the animal models of epilepsy and in human intractable epilepsy. The difference between pharmacosensitive epilepsy and pharmacoresistant epilepsy remains poorly understood. The present study aimed to observe the hippocampus SV2A protein expression in amygdale-kindling pharmacoresistant epileptic rats. The pharmacosensitive epileptic rats served as control. Amygdaloid-kindling model of epilepsy was established in 100 healthy adult male Sprague-Dawley rats. The kindled rat model of epilepsy was used to select pharmacoresistance by testing their seizure response to phenytoin and phenobarbital. The selected pharmacoresistant rats were assigned to a pharmacoresistant epileptic group (PRE group). Another 12 pharmacosensitive epileptic rats (PSE group) served as control. Immunohistochemistry, real-time PCR and Western blotting were used to determine SV2A expression in the hippocampus tissue samples from both the PRE and the PSE rats. Immunohistochemistry staining showed that SV2A was mainly accumulated in the cytoplasm of the neurons, as well as along their dendrites throughout all subfields of the hippocampus. Immunoreactive staining level of SV2A-positive cells was 0.483 ± 0.304 in the PRE group and 0.866 ± 0.090 in the PSE group (P < 0.05). Real-time PCR analysis demonstrated that 2(-ΔΔCt) value of SV2A mRNA was 0.30 ± 0.43 in the PRE group and 0.76 ± 0.18 in the PSE group (P < 0.05). Western blotting analysis obtained the similar findings (0.27 ± 0.21 versus 1.12 ± 0.21, P < 0.05). PRE rats displayed a significant decrease of SV2A in the brain. SV2A may be associated with the pathogenesis of intractable epilepsy of the amygdaloid-kindling rats.
Amygdala ; drug effects ; metabolism ; physiopathology ; Animals ; Anticonvulsants ; pharmacology ; Disease Models, Animal ; Drug Resistance ; Electric Stimulation ; Epilepsy ; drug therapy ; genetics ; metabolism ; pathology ; Gene Expression Regulation ; Hippocampus ; drug effects ; metabolism ; physiopathology ; Kindling, Neurologic ; drug effects ; genetics ; metabolism ; pathology ; Male ; Membrane Glycoproteins ; genetics ; metabolism ; Nerve Tissue Proteins ; genetics ; metabolism ; Phenobarbital ; pharmacology ; Phenytoin ; pharmacology ; RNA, Messenger ; genetics ; metabolism ; Rats ; Rats, Sprague-Dawley ; Synaptic Transmission ; Synaptic Vesicles ; drug effects ; metabolism ; pathology