20-Hydroxyecdysone accelerates the flow of cells into the G1 phase and the S phase in a male accessory gland of the mealworm pupa (Tenebrio molitor)

The cells of the bean-shaped accessory glands of mealworms proliferate through the first 7 days of the 9-day pupal stage. Immediately after larval-pupal ecdysis, 25-27% of the cells were in the G1 phase, 60-65% were in the G2 phase, and the balance were in S phase. Over the first 4 days of normal development, the S fraction gradually increased, to reach its highest level in the mid-pupa at the time of the major ecdysteroid peak (Delbecque et al., 1978). Thereafter, the S fraction declined until over 95% of the cells had accumulated in G2 on Day 8. When 0-day pupal glands were explanted into Landureau's S-20 medium for 6 days, the G1 fraction remained fairly constant (25-30%) while S and the G2 fractions fluctuated. On the first day in vitro, the G2 fraction declined and the S fraction rose. On the second day in basal media, the S fraction fell and G2 rose correspondingly until 70% of the cells reached G2 when cycling stopped on the third day. With addition of 20-hydroxyecdysone to 0-day cultures, the S fraction increased quite sharply. It remained large for all 6 days of the experiment in the continuing presence of hormone. A 1-day pulse of hormone produced a transient increase in S. We blocked cell cycling with hydroxyurea in a stathmokinetic experiment and showed that 20-hydroxyecdysone accelerated the flow of cells from the G2 phase to the G1 phase by 2.5-fold. An increase in the G1 fraction was detected within 10 hr of hormone administration and the effect was dose-dependent with an ED50 of 5 X 10(-7) M for 20-hydroxyecdysone. We conclude that 20-hydroxyecdysone acts at a control point in the G2 phase. Incubation of the glands with 20-hydroxyecdysone for only 30-60 min followed by washout stimulated the flow from G2 to G1 and the effect persisted after transfer of the tissues to hormone-free media. Dose-dependent stimulation also occurred with ponasterone A (ED50 3 X 10(-9] but not with cholesterol.     

The effects of extracorporeal shock wave lithotripsy on antioxidant enzymes in erythrocytes

The effects of extracorporeal shock wave lithotripsy (ESWL) on patients undergoing ESWL for renal stone treatment have been studied using activities of glucose-6-phosphate dehydrogenase (G6PDH), superoxide dismutase (SOD) and catalase (CAT), and levels of malondialdehyde (MDA) in the erythrocyte haemolysate. The study included 23 patients (eight women, 15 men with an age range of 23-57 years). Blood samples were taken 5 min before ESWL, in addition to 1 h and 5 days after termination of treatment. Enzyme activities and MDA levels in erythrocytes were measured spectrophotometrically. When compared with the values obtained before ESWL, erythrocyte G6PDH (p = 0.015), SOD (p = 0.036) and CAT (p = 0.01) activities were found to be significantly reduced at the first hour after ESWL. On the fifth day after ESWL, erythrocyte enzyme activities were normalized to the values obtained before ESWL. Although there was a significant difference between values before and 1 h after ESWL (p = 0.003), no difference was detected between 1 h after ESWL and 5 days after ESWL (p > 0.05) in terms of MDA values. The findings of the present study revealed that erythrocyte lipid peroxidation might be induced and antioxidative defence mechanism may be transiently impaired by ESWL.     

Metabolic Activity of Isolated Leaf Cells of Phaseolus vulgaris in Relation to Leaf Development

Mesophyll cells were isolated from primary leaves of 5- to 21-day Phaseolus vulgaris plants. The rate of photosynthesis and respiration, and RNA, protein, and lipid synthesis was determined for these cells. Appropriate ¹⁴C substrates and product purification procedures were used for each process prior to liquid scintillation counting. The size of the leaves increased about 5-fold between days 5 and 11, and then remained relatively constant. The greatest increase in size occurred between days 5 and 6. The age of the leaf from which the cells were isolated had a pronounced effect on the rate of all of these processes. The largest changes occurred during the period of leaf expansion (days 5-11). Initially the rate of RNA, protein, and lipid synthesis increased rapidly, maintained a maximum rate for only 1 day (day 6 or day 7), and then declined. The rate of photosynthesis increased more slowly reaching a maximum at day 9, remained relatively constant until day 15, and then declined. The rate of respiration decreased during the first 4 days to low level which was maintained throughout the experiment. The time course patterns of these biochemical processes in isolated cells were similar to those which have been reported for intact leaves. It seems that isolation of leaf cells does not modify their metabolic activity.     

Temporal changes in body mass, body composition and metabolism of gibel carp Carassius auratus gibelio during food deprivation

To investigate the response to starvation, gibel carp Carassius auratus gibelio [12.5 ± 0.03 g (mean ± SE, n = 24)] were deprived of food at 25.8 ± 0.2°C (mean ± SE, n = 56) for 56 days. Body mass, proximate composition in whole body and muscle, and respiration were measured at 7‐day intervals. Body mass decreased with prolongation of deprivation, with a significant decline recorded after 7 days deprivation. Fish lost 22% of their fresh mass and 34% of dry mass after 56 days. Fish lost 38% of the body lipid over the first 7 days, and lost body lipid at a rate of 0–11% per week over the remaining 49 days. Body protein was lost at 1–5% per week throughout deprivation. Compared with the initial composition, body lipid concentration was lower and ash concentration higher on day 7. Water as a percentage of body mass was higher after 28 days, and protein concentration lower after 42 days, than at the start of deprivation. Muscle lipid and protein concentration was lower, and % water higher, after 7 days than at the start of deprivation, whereas muscle ash concentration was relatively constant during deprivation. After 56 days, fish lost body water by 18%, body lipid by 84%, body protein by 30%, and body energy by 45%. Oxygen consumption rate dropped from day 1 to day 3, increased from day 4 to day 14, gradually decreased from day 15 to day 35, and maintained a relatively constant level from day 36 to day 56. Results of the present experiment reveal that gibel carp utilize body lipid as a major energy source in the first 7 days of food deprivation, then turn to body protein as an energy fuel when lipid reserves are heavily depleted. Oxygen consumption is maintained at a relatively low and constant level when most lipid reserves are exhausted.     

The effect of thymosin fraction 5 on lipid peroxidation in rabbits fed a high-cholesterol diet

Plasma and erythrocyte lipid levels and susceptibility of erythrocytes to lipid peroxidation were determined in rabbits fed diet containing 2% (w/w) cholesterol, for 3 months. Hypercholesterolemic rabbits had high plasma and erythrocyte lipid peroxide levels as compared to control rabbits. After high-cholesterol diet, the rabbits in the experimental group were divided into two groups. The first group was fed a normal diet for 21 days and the second group was given normal diet plus thymosin F5 injections every other day for the same period. At the end of this period, plasma and erythrocyte lipid peroxide levels were significantly decreased in the group injected with thymosin F5.     

Efficacy of intervention strategies for bioremediation of crude oil in marine systems and effects on indigenous hydrocarbonoclastic bacteria

There is little information on how different strategies for the bioremediation of marine oil spills influence the key indigenous hydrocarbon-degrading bacteria (hydrocarbonoclastic bacteria, HCB), and hence their remediation efficacy. Therefore, we have used quantitative polymerase chain reaction to analyse changes in concentrations of HCB in response to intervention strategies applied to experimental microcosms. Biostimulation with nutrients (N and P) produced no measurable increase in either biodegradation or concentration of HCB within the first 5 days, but after 15 days there was a significant increase (29%; P < 0.05) in degradation of n-alkanes, and an increase of one order of magnitude in concentration of Thalassolituus (to 10(7) cells ml(-1)). Rhamnolipid bioemulsifier additions alone had little effect on biodegradation, but, in combination with nutrient additions, provoked a significant increase: 59% (P < 0.05) more n-alkane degradation by 5 days than was achieved with nutrient additions alone. The very low Alcanivorax cell concentrations in the microcosms were hardly influenced by addition of nutrients or bioemulsifier, but strongly increased after their combined addition, reflecting the synergistic action of the two types of biostimulatory agents. Bioaugmentation with Thalassolituus positively influenced hydrocarbon degradation only during the initial 5 days and only of the n-alkane fraction. Bioaugmentation with Alcanivorax was clearly much more effective, resulting in 73% greater degradation of n-alkanes, 59% of branched alkanes, and 28% of polynuclear aromatic hydrocarbons, in the first 5 days than that obtained through nutrient addition alone (P < 0.01). Enhanced degradation due to augmentation with Alcanivorax continued throughout the 30-day period of the experiment. In addition to providing insight into the factors limiting oil biodegradation over time, and the competition and synergism between HCB, these results add weight to the use of bioaugmentation in oil pollution mitigation strategies.     

Changes in the activities of nitrogen assimilation enzymes ofLolium perenne L. during regrowth after cutting

The activities of key enzymes involved in N assimilation were investigated after defoliation of 6-week-old ryegrass plants grown in water culture conditions. In a first experiment, nitrate reductase, glutamine synthetase and glutamate dehydrogenase activities were measured in roots, stubble and leaves on the day of cutting and at 7-day intervals over the following 5-week period of regrowth. Ammonia assimilation enzymes showed little change whereas the nitrate reductase activity sharply decreased 2 weeks after clipping. In a second experiment, the nitrate reductase activity was measured at 2- or 3-day intervals 1 week before and 3 weeks after clipping.In vivo andin vitro assays both showed an increasing activity in leaves up to 8 days after cutting while root activity decreased. The opposite changes then occurred and both organs recovered their initial nitrate reductase activity levels after 12–14 days of regrowth. These fluctuations in nitrate reductase activity were considered to be related to the capacity for C assimilation and the nitrate availability.     

Topiramate and Vitamin E Modulate the Electroencephalographic Records,Brain Microsomal and Blood Antioxidant Redox System in Pentylentetrazol-Induced Seizure of Rats

We investigated the effects of vitamin E and topiramate (TPM) administrations on pentylentetrazol (PTZ)–induced blood and brain toxicity in rats. Forty rats were randomly divided into five equal groups. The first and second groups were used for the control and PTZ groups, respectively. Fifty or 100 mg TPM were administered to rats constituting the third and fourth groups for 7 days, respectively. The TPM and vitamin E combination was given to animals in the fifth group. At the end of 7 days, all groups except the first received a single dose of PTZ. Blood and brain samples were taken at 3 hrs after PTZ administration. Lipid peroxidation levels of plasma, erythrocyte, brain cortex and brain microsomal fraction; nitric oxide levels of serum; and the number of spikes and epileptiform discharges of the EEG were increased by PTZ administration. Plasma and brain vitamin E concentration, erythrocyte glutathione peroxidase (GSH-Px) activity and latency to first spike of the EEG were decreased by PTZ. Plasma lipid peroxidation levels in the third group and plasma and erythrocyte lipid peroxidation levels in the fifth group were decreased compared to the second group, whereas brain vitamin C, vitamin E, erythrocyte GSH-Px and reduced glutathione (GSH) values increased in the fifth group. Brain microsomal GSH levels and EEG records in the third, fourth and fifth groups were restored by the TPM and vitamin E treatment. In conclusion, TPM and vitamin E seems to have protective effects on PTZ-induced blood and brain toxicity by inhibiting free radicals and supporting the antioxidant redox system.     

Growth of Perca fluviatilis larvae fed with Artemia spp. nauplii and the effects of initial starvation

Experiments were performed to test the growth and survival of perch larvae fed with Artemia spp. nauplii and to determine the most advantageous time of first feeding. During a first experiment, perch larvae were divided into groups according to their hatching dates. Daily ingestion of Artemia spp. nauplii began significantly 2 days after mass larvae hatching. By day 7, the daily prey acceptance was over 75% among the separate larvae groups. During a second 14-day feeding experiment, larvae fed after a 2- or a 3-day delay showed the best growths: 12.5 mm and 13.7 mg. There was no significant difference (P > 0.05) among survival rates (85.3%) of perch larvae fed after a 1-, 2- or 3-day delay.     

Coping with resource variation: Effect of constant and variable intervals between feeding on reproductive performance at first spawning of female three-spined sticklebacks

Female three-spined sticklebacks Gasterosteus aculeatus exposed to spring conditions (14) C and a photoperiod of 16L: 8D), and fed 6% of initial body weight per day of enchytraeid worms (controls) over 56 days, or either at regular 3-day or variable 1–5-day intervals between feeds, did not differ significantly in the proportion spawning (72%), in time to first spawning (24·5 days), in fecundity at first spawning (34) or in egg diameter (1·4 mm) at first spawning. There was no significant effect of feeding regime on lipid concentration of females immediately after first spawning (18·8% dry weight), but the experimental females had a slightly lower dry matter content and lower fresh and dry liver weight than controls. Eggs of females on the variable-interval regime had a higher lipid content than eggs from other groups. Days to spawning was correlated inversely and fecundity positively with initial length. Females adjusted their food intake to compensate for short periods of food deprivation, allowing them to maintain their reproductive performance at first spawning.     

Lipid composition of alveolar macrophage plasma membrane during postnatal development

This study was undertaken to define the age-related alterations in lipid composition that resident rabbit alveolar macrophages (AM) undergo during postnatal development. The eventual goal is to correlate these changes with the functional maturation of these cells. The number of AM recorded from total lung lavages rose markedly during the first 14 days of life, from 4.9 X 10(5) to 1.1 X 10(7). Adult lungs yielded 1.1 X 10(8) AM. A gradual but significant increase in fluorescence polarization (P) was observed during development when purified AM plasma membranes were tagged with the probe 1,6-diphenyl-1,3,5 hexatriene trimethyl ammonium. The rise ranged from a mean P value of less than or equal to 0.22 to 0.24 (p less than 0.001) for AM plasma membranes from rabbits 1- or 7-day-old to 30- or 150-day-old rabbits, respectively. This finding suggests that the fluidity of the AM plasma membrane decreased during postnatal development. Palmitic, stearic, oleic, and linoleic acids were the most prevalent fatty acids found in the neutral lipid fraction of the AM plasma membrane throughout development. The content of stearic acid rose from 10 to 16%, arachidonic acid rose from 2.8 to 9%, myristic acid decreased from 3.2 to 1.3%, palmitic acid decreased from 42 to 36%, and oleic and linoleic acids changed relatively little during the first 30 days of life. The levels of docosatetraenoic and docosapentaenoic increased gradually during the first 14 days of life, and by 30 days of life the levels declined to that observed at birth. The sum of these changes resulted in an increase in the ratio of unsaturated to saturated fatty acids (1 to 1.15) in the neutral lipid fraction. During the first month of life, the neutral lipid fatty acid pool in the total lipid fraction of AM plasma membrane increased from 12 to 18 mole %, cholesterol increased from 7 to 14 mole %, and total phospholipids decreased from 81 to 67 mole %. These changes resulted in increasing the cholesterol to phospholipid ratio from 0.09 at birth to 0.23 by 150 days of life. The levels of all three major lipid fractions were comparable at 30 days and 150 days of life. Adult levels of choline phosphoglycerides, the predominant phospholipid, were observed by 7 days of life to have decreased from 47 to 34.5 mole %, and the levels of ethanolamine phosphoglycerides and sphingomyelin increased from 17.5 to 25 mole % and from 9 to 13 mole %, respectively. Adult levels of lyso-bis-phosphatidic acid were reached by 30 days of life increasing from 8.2 to 17.8 mole %.(ABSTRACT TRUNCATED AT 400 WORDS)     

Effects of ethanol and haloperidol on plasma levels of hepatic enzymes, lipid profile, and apolipoprotein in rats.

This work studied the effects of ethanol in the absence and presence of haloperidol under two experimental conditions. In protocol 1, rats were treated daily with ethanol (4 g/kg, p.o.) for 7 days, and received only haloperidol (1 mg/kg, i.p.) from the 8th day to the 14th day. In protocol 2, animals received ethanol, and the treatment continued with ethanol and haloperidol from the 8th day to the 14th day. Results show increases in alanine transaminase (ALT; 48% and 55%) and aspartate transaminase (AST; 32% and 22%) levels after ethanol or haloperidol (14 days) treatments, as compared with controls. Apolipoprotein A-1 (APO A1) levels were increased by haloperidol, after 7- (148%) but not after 14-day treatments, as compared with controls. Levels of lipoprotein (high-density lipoprotein (HDL-C)) tended to be increased only by ethanol treatment for 14 days. ALT (80%) and AST (43%) levels were increased in the haloperidol plus ethanol group (protocol 2), as compared with controls. However, an increase in APO A1 levels was observed in the haloperidol group pretreated with ethanol (protocol 1), as compared with controls and ethanol 7-day treatments. Triglyceride (TG) levels were increased in the combination of ethanol and haloperidol in protocol 1 (234%) and 2 (106%), as compared with controls. Except for a small decrease in haloperidol groups, with or without ethanol, as related to ethanol alone, no other effect was observed in HDL-C levels. In conclusion, we showed that haloperidol might be effective in moderating lipid alterations caused by chronic alcohol intake.     

Effects of diet and folate on levels of micronucleated polychromatic erythrocytes

We describe a study examining the effects of fried beef consumption on the frequency of micronuclei in RNA-positive polychromatic erythrocytes (PCEs) in humans. 5 splenectomized individuals participated in a 2-week experiment consisting of 3 phases. During the first and last phases the subjects refrained from eating cooked meat for 4–5 days. This was designed to clear their system of mutagens found in cooked-meat products. In the second phase each person ate a similar diet, but also consumed 4 quarter-pound well-done hamburgers per day for 4 days. Erythrocyte-folate levels were also measured for each donor. No association between diet phase and micronucleus frequencies was observed among the 2 subjects with normal levels of folate. However, among the 3 low-folate donors, the frequency of micronucleated PCEs appeared to be associated with diet. Micronucleus frequencies began to increase 1 day following onset of the beef phase, and started to decline 1 day after finishing this phase. These observations are in agreement with erythrocyte maturation kinetics following short-term exposure. A repeat study performed on one of the low-folate donors consisted of two beef phases separated by a vegetarian phase. Beef in one phase was fried (high in mutagenic amino-imidazoazaarenes [AIAs]) while the beef in the other phase was fried after first being microwave-cooked (low in AIAs). Significant increases in the micronucleus frequency were not observed in this experiment, suggesting that AIAs formed during frying were not solely responsible for the induction of micronuclei     

Host cell cytotoxicity, cellular repopulation dynamics, and phase-specific cell survival in X-irradiated rat rhabdomyosarcoma tumors

Postirradiation tumor volume response, cellular repopulation dynamics, cell-cycle perturbations, and phase-specific cell survival were characterized in rat rhabdomyosarcoma R-1 tumors (the R2C5 subline) following an in situ 10-Gy dose of 225-kVp X rays. This X-ray dose produced a 7.5-day delay in tumor growth to twice the volume measured at the time of irradiation, and reduced the initial surviving fraction of R2C5 cells to 0.17 as measured by the excision assay procedure. The surviving fraction of R2C5 cells returned to unity by the 16th day after tumor irradiation. On the basis of flow cytometry measurements of DNA content in tumor cells stained with a noncytotoxic concentration of Hoechst 33342 (5 microM, 2 h, 37 degrees C), a transient G2 block was observed 1 day after irradiation. Flow cytometry measurements also demonstrated that the tetraploid R2C5 cells constituted only 30% of the total tumor cell population, with the remainder being diploid host cells comprised of macrophages, monocytes, lymphocytes, and granulocytes. Large numbers of host cells infiltrated the irradiated tumors, leading to an increase in the percentage of diploid cells by Day 2 and reaching a level of more than 80% of the total tumor cell population by 4 to 8 days after irradiation. The influx of host cells into irradiated tumors was correlated temporally with a significant 12-fold decrease in the surviving fraction of R2C5 cells that occurred between Days 2 and 4 postirradiation. When the diploid host cell population was removed by cell sorting procedures, the surviving fraction of R2C5 cells at Day 4 was substantially greater than that in the presence of the host cells. Experiments involving the mixing of 4/1 and 12/1 ratios of diploid host cells and tetraploid tumor cells isolated from irradiated and unirradiated tumors demonstrated that the cytotoxic effect of the host cells was specific for the irradiated tumor cells. The significant toxic effect of host cells on irradiated tumor cells was observed only at 2 to 4 days after irradiation, and not at earlier or later times. The data obtained in these experiments indicate that the immunogenicity of R2C5 cells is increased significantly by irradiation, and a resultant cell-mediated host immune response produced a delayed decrease in tumor cell survival that is most pronounced 4 days after irradiation. The cell survival characteristics of R2C5 cells in different cell-cycle phases were found to be similar through the 16-day postirradiation interval that was studied.(ABSTRACT TRUNCATED AT 250 WORDS)     

Elevated serum beta-glucuronidase reflects hepatic lysosomal fragility following toxic liver injury in rats.

The level of serum beta-glucuronidase increases in various pathological conditions, including liver disorders. The aim of this investigation was to study the changes in liver lysosomal membrane stability during experimentally induced hepatic fibrosis that may result in the elevation of serum beta-glucuronidase. Liver injury was induced by intraperitoneal injections of N-nitrosodimethylamine (NDMA) in adult male albino rats over 3 weeks. The progression of fibrosis was evaluated histopathologically as well as by monitoring liver collagen content. Lipid peroxides and beta-glucuronidase levels were measured in the liver homogenate and subcellular fractions on days 0, 7, 14, and 21 after the start of NDMA administration. Serum beta-glucuronidase levels were also determined. A significant increase was observed in beta-glucuronidase levels in the serum, liver homogenate, and subcellular fractions, but not in the nuclear fraction on days 7, 14, and 21 after the start of NDMA administration. Lipid peroxides also increased in the liver homogenate and the lysosomal fraction. The measurement of lysosomal membrane stability revealed a maximum lysosomal fragility on day 21 during NDMA-induced fibrosis. In vitro studies showed that NDMA has no significant effect on liver lysosomal membrane permeability. The results of this investigation demonstrated that lysosomal fragility increases during NDMA-induced hepatic fibrosis, which could be attributed to increased lipid peroxidation of lysosomal membrane. In this study, we also elucidated the mechanism of increased beta-glucuronidase and other lysosomal glycohydrolases in the serum during hepatic fibrosis.     

Ischemia-Induced Alterations in Lipid Metabolism of the Gerbil Cerebral Cortex: I. Changes in Free Fatty Acid Liberation

Abstract: Does the impaired lipid metabolism during nonlethal transient ischemia truly recover within a few hours after recirculation? In an attempt to answer this question, we first investigated the time course of the changes in the amount and composition of free fatty acids (FFAs) accumulated during 5-min ischemia and after various postischemic recirculation durations (3 min, 1 h, 24 h, 3 days, and 6 days) in the gerbil cerebral cortex. Then those of FFAs liberated in response to the second 5-min ischemia at various recirculation intervals (3 min, 1 h, 3 days, and 6 days) following the initial one were also measured to evaluate the changes in the cellular response. The former study disclosed that the FFA levels transiently returned to the control levels at 1-h recirculation, increased again a few days after the onset of recirculation, followed by the final return to the control levels after 6-day recirculation. The latter study disclosed that the cellular response to the second ischemia was quite different from that to the initial one even after 6-day recirculation, suggesting that membrane lipid metabolism had not yet been recovered even at such a late period. We discuss the significance of the alterations in lipid metabolism.     

Sexual behaviour in castrated rabbits treated with varying doses of testosterone

Sexual behaviour was studied in castrated rabbits injected every third day with 1, 7·5, 15 or 30 mg TP, during a 120-day period. Castration led to a very pronounced reduction of sexual activity. This was restored to precastration levels by the three larger doses used about 60 days after the beginning of hormone treatment. The lowest dose did not cause any significant increase in sexual activity. About 70 days after the hormone treatment ceased, almost all sexual activity had disappeared. The correlation coefficients obtained between the various parameters of sexual activity ranged between 0·21 and 0·54. The present observations are discussed in relation to results obtained with other species.     

Long-term intracellular chromium partitioning with subsurface bacteria

Subsurface bacteria were used to study the kinetics of chromate uptake and the internal distribution of the chromium that is taken up by these cells using two equilibration periods (1 and 50 days). Cells that were exposed to chromate for 50 days (to simulate in-situ conditions) were able to sequester up to 200% more chromium per unit mass of cells than were cells that were exposed for only 1 day. Chromium distributions showed an increase in chromium sorption by the cell wall, by the membrane and ribosome, and by the soluble fraction after a 50-day equilibration period compared to after 1 day of equilibration. Killed cell controls suggest that active transport of chromate is the method of intracellular accumulation during the 50-day equilibration period.     

Carbamazepine induces multiple cytochrome P450 subfamilies in rats

We compared the effect of three different doses (30, 60, and 100 mg/kg) of carbamazepine (CBZ) administered intraperitoneally for 1, 3, and 7 days on the activity and protein content of hepatic cytochrome P450 (CYP) subfamilies in Sprague-Dawley rats. After 3-day- and 7-day administration with CBZ, the total CYP content had increased in a dose-dependent fashion. Among six enzyme activities examined, only aniline hydroxylase activity remained unchanged after 7-day treatment with CBZ. Pentoxyresorufin O-deethylase activity showed the most significant increase and was induced up to 7 days in a time-dependent fashion. Pretreatment of rats with cycloheximide significantly suppressed the pentoxyresorufin O-deethylase induction by one dose of 100 mg/day CBZ. Immunoblot analysis showed a significant correlation between the protein content of each isoenzyme examined and its activity except CYP2E1 after 7-day treatment with CBZ. Similar results were obtained in the mRNA levels of CYP subfamilies. These results suggested that CBZ may induce multiple CYP subfamilies, except CYP2E1, and the activity and the protein content of CYP2B showed the greatest increase with increased CYP2B mRNA.