• 대한의생명과학회지
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• 제7권3호
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• pp.111-116
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• 2001

To investigate an effect of aging on the xylene metabolism in liver damaged animals, a study was conducted. 50% carbon tetrachloride ($CCl_4$) in olive oil (0.1 ml/100 g body weight) was intraperitoneally given to 5-week and 12-week rats 12 times every other day and then one dose of 50% xylene in olive oil (0.25 ml/100 g body weight) was intraperitoneally given to the rats, and after 24 hr, the animals were sacrificed. On the basis of the functional findings in rat liver, ie, serum levels of alanine aminotransferase activity, liver protein and malonedialdehyde contents, 5-week rats showed less liver damage than 12-week rats. The increasing rate of urinary methylhippuric acid concentration to the control was significantly higher in 5-week rats than 12-week rats in case of xylene treatment after induction of liver damage. On the other hand, liver damaged 5-week rats showed significant rise of hepatic cytochrome P45O content compared with the liver damaged 12-week rats by the xylene treatment. And increasing rate of hepatic alcohol or aldehyde dehydrogenase activities to each liver damaged animals was higher tendency in 5-week rats than 12-week rats by the xylene treatment. In conclusion, 5-week rat showed greater metabolic rate of xylene than 10-week rats in case of liver injury because 5-week rats led to a slight liver damaged compared with 12-week rats.

• 대한의생명과학회지
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• 제5권1호
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• pp.59-66
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• 1999

실험동물에 xylene의 반복 투여가 이물질의 대사에 어떠한 영향을 미치는지를 알아보기 위하여 흰쥐에 m-xylene과 olive oil의 동량혼합액을 체중 100 g당 0.25 ml씩 2일 간격으로 1, 4, 8, 12 및 16회 복강으로 투여한 다음 마지막 투여 24시간 후에 처치하여 다음과 같은 결과를 얻었다. 요 중 m-methylhippuric acid함량은 m-xylene 4회 투여군의 경우 1회 투여군에 비하여 약 56%의 유의한 증가를 보였으며 이후 12회 투여까지 유사한 결과를 나타내었으나 m-xylene 16회 투여시에는 xylene 1회 투여군 치와 유사한 치로 감소되었다. 그리고 간조직의 microsomal aniline hydroxylase와 alcohol dehydrogenase 활성은 m-xylene 12회 투여시 까지는 대체적으로 점진적인 증가를 보였으나 이후 16회 투여시에는 12회 투여군에 비하여 유의한 감소를 보였다. 또한 aldehyde dehydrogenase 활성은 m-xylene투여 회수에 비례해서 전 실험기간 동안 감소되었으며 특히 16회 투여군에서 본 효소활성의 현저한 감소를 보였다. 한편 본 실험조건에서 투여기간에 따른 전자현미경적 미세구조의 변화는 초기에 활면소포체의 증식이 보이다가 16회 투여군에서는 활면소포체가 감소되고 조면소포체가 증가되었다. 이상 실험결과는 흰쥐에 있어서 xylene투여 회수에 따라서 요 중 m-methylhippuric acid의 농도 변동이 초래되며 이는 효소단백 유도에 따른 xylene 대사효소 활성 변동에 기인된 결과로 생각된다.

• 대한의생명과학회지
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• 제9권2호
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• pp.93-98
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• 2003

To investigate the cyclohexane and xylene mixture treatment on the liver damage, the rats were treated by the mixture of cyclohexane and xylene (CH＋X) and then, liver damage was demonstrated by liver function findings based on liver weight/body weight, serum level of alanine aminotransferase (ALT), xanthine oxidase (XO) and then compared with cyclohexane treated group (CH group) and xylene-treated group (X). The CH＋X group showed merely severer liver damge than CH or X group. On the other hand, CH＋X group showed lower activity of hepatic cytochrome P-450 dependent aniline hydroxylase (CYPdAH) than CH or X group, but no statical differences were demonstrated among three experimental groups. Especially the hepatic GSH content was merely declined than CH or X group and the activity of hepatic GST was higher in CH＋X group than CH or X group. In conclusion, cyclohexane and xylene mixture treated animals showed merely severer liver damage than cyclohexane or xylene treated group and such a fact may be caused by inhibition of cyclohexane or xylene metabolism and oxygen free radical.

• 대한의생명과학회지
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• 제6권3호
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• pp.193-199
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• 2000

실험동물에 있어서 연령 차이에 따라서 xylene 독성이 어떠한 차이가 있는지를 검토하는 일환으로 5주령 및 12주령 흰쥐에 50% m-xylene을 체중 100 g 당 0.25 ml씩 1회 투여한 다음 24시간 후에 처치하여 다음과 같은 결과를 얻었다. Xylene투여로 인한 요 중 methylhippuric acid 함량은 5주령군이 12주령군에 비해 현저하게 높게 나타났다. 그리고 간조직 중 cytochrome P-450 함량은 대조군에 있어서 5주령군이 12주령군 보다 약 50% 정도 낮게 나타났으나 xylene 투여로 인한 cytochrome P-450 함량 증가율은 12주령군 보다 5주령군에서 높게 나타났다. 간 alcohol dehydrogenase 활성치도 대조군에 있어서는 5주령군이 12주령 보다 약 35% 정도 낮게 나타났으나 xylene 투여로 인한 본 효소의 활성 증가율은 5주령군에서 오히려 높게 나타났다. 그러나 간 aldehyde dehydrogenase 활성치는 대조군 및 xylene 투여군 모두 5주령과 12주령간에 유의한 차이를 나타내지 않았다. 한편 xylene 투여시 체중 당 간무게, 간조직 malondialdehyde 함량 및 혈청 ALT 활성 변동을 통하여 간손상 정도를 상호 비교 관찰하였을 때, 12주령군이 5주령 실험동물 보다 간손상이 다소 심하게 나타남을 알 수가 있었다. 이상 실험결과는 연령에 따라 xylene에 의한 간손상의 차이는 이물질의 생체내 대사율이 달리 나타나기 때문일 것으로 생각된다.

• Journal of Preventive Medicine and Public Health
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• 제37권4호
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• pp.321-328
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• 2004

Objectives : The purpose of this study was to investigate the effect of genetic polymorphism of cytochrome P450 2E1 (CYP2E1) and aldehyde dehydrogenase 2 (ALDH2) on the xylene metabolism. Methods : Among 247 workers, 116 were occupationally exposed to xylene and 131 were not. Workers exposed to xylene had different work such as spray, touch-up, mix & assist, and pre-treat. Questionnaire variables were age, sex, use of personal protective equipment, smoking, previous night's drinking and work duration. The urinary methylhippuric acid was measured in the urine collected in the afternoon and corrected by urinary creatinine concentration. The genotypes of CYP2E1 and ALDH2 were investigated by using PCR-RFLP (polymerase chain reaction-restriction fragment length polymorphism) methods with DNA extracted from venous blood. Results : 1. The urinary concentrations of o-, m-, and p-methylhippuric acid and total methylhippuric acid in the exposed group were significantly higher than those in the non-exposed group (p<0.001). 2. In multiple regression analysis, the urinary methylhippuric acid concentration was significantly influenced by exposure grade (Job-exposure matrixes), smoking, drug use and kind of protective equipment (p<0.1). 3. Genetic polymorphism of CYP2E1 and ALDH2 did not affect urinary methylhippuric acid level in the exposed group (p>0.05). Conclusions : Exposure grade, smoking, drug use and kind of protective equipment affected urinary methylhippuric acid level, whereas genetic polymorphism of CYP2E1 and ALDH2 did not. However, further investigation for the effect of genetic polymorphism on the metabolism of xylene with a larger sample size is needed.

• 한국환경보건학회지
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• 제27권2호
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• pp.10-16
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• 2001

To evaluate an effect of circadian variation on the xylene metabolizing enzyme activities, 50% m-xylene in olive oil(0.25 $m\ell$/100g body weight) was intraperitoneally administered to the rats every other day for 6 days both in the night; 24:00 and the day; 12:00. Then animals were sacrigiced at 8hr after last injection of m-xylene. Hepatic microsomal cytochrome p450 contents were more increased both in control and xylene treated rats of night phase than those of day phase. But the activity of hepatic alcohol dehydrogenase(ADH) in control of night phase showed the similar value with that in those of day phase and xylene treated rats of day phase showed an increasing tendency of hepatic ADH activity as those of night phase showing similar activity. Furthermore, control rats of night phase than those of day phase. And by xylene treatment, enzyme activities of rats of day phase were higher tendency in rats of control but those of night phase were somewhat inhibited. Besides, xylene-treated animals of night phase showed increasing tendency of urinary methylhippuric acid concentration compared with those of day phase. On the other hand, liver weight per body weight(%), hepatic lipid peroxide content and serum xanthine oxidase activity were higher in night phase. And the activities of hepatic oxygen free radical metabolizing enzymes such as xanthine oxidase, gluthathione S-transferase, and xylene-treated rats of night phase than those of day phase. In conclusion, it can be hypothesized on the basis of the results that the accumulation rate of m-xylene intermediate metabolite, i.e. m-methylbenzaldehyde in liver tissus may be higher in night phase than in day phase and it may be responsible for higher liver toxicity in bight phase than in day phase.

• Toxicological Research
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• 제11권2호
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• pp.205-213
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• 1995

This study was undertaken to investigate the effects of organic solvents on xenobiotic metabollzing enzyme system in vivo by meaas of experimental conditions i.e. (1) single group which was treated by benzene (B), toluene (T) and xylene (X), respectively, (2) combination group which was treated by mixture of benzene+toluene (BT), benzene+xylene (BX), and toluene+xylene (TX), respectively, (3) mixture group which was treated by benzene+ toluene+xylene mixture (M), and to interpreat the interaction between the organic solvents metabolizing enzymes. 1. The contents of cytochrome P-450 in liver microsomes were increased (p < 0.01) in organic solvents treated groups, and the contents of cytochrome P-450 were increased by following order of B < T < M < BT=BX < X < TX. 2. The activity of cytochrome P-450 dependent AHHase was significantly higher in organic solvents treated groups than in control group (p < 0.01), and the activity of AHHase was increased by following order of B < T < BT=BX=TX=xylene < M. 3. The activity of NADPH P-450 reductase was significantly higher in organic solvents treated groups than in control group (p < 0.01), and the order of M < combinated group < X < T

• 대한예방의학회:학술대회논문집
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• 대한예방의학회 1995년도 제47차 추계 학술대회 연제집
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• pp.295-296
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• 1995

• 미생물학회지
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• 제17권1호
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• pp.25-41
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• 1979

A strain able to grow up m-toluate minimal medium has been isolated after selective enrichment and given the name T81X, which was later identified as pseudomonase putida according to its morphological and biochemical characteristics. After treatment with plasmied specific curing agent, mitomycin C, followed by replica plating on m-toluate and xylene minimal agar plate, T81Xstrain has been shown to harbour a curable plasmid relating to the m-toluate and xylene metabolism. Spontaneous curing frquency of this plasmid was also greatly enhanced by growing on benzoate minimal medium. After then, it was also xylene metabogrowing on benzoate minimal medium. After then, it was found to be conjugally nontransmissible. From the comparative investigation of catechol 1,2-oxygenase and catechol 2,3-oxygenase activities in wild type and cured strain on various growth substrate, it appeared that T81X strain has both of these two enzymes while cured strain has catechol 1,2-oxygenase only. Growing on m-toluate minimal medium T81X strain should carry the genetic information necessary for coding the catechol 1,2-oxygense induced by m-toluate or benzoate, on that curable plasmid.

• 한국산업보건학회지
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• 제19권1호
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• pp.73-79
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• 2009

This study was undertaken to investigate the effects of single and combined exposure of toluene (T) and xylene (X) on the cytochrome-450(CYP)-mediated metabolizing capacity, induction of CYP isozymes and the excretion of their metabolites in urine. Animal were adults male Sprague-Dawley (SD) rats and divided into 4 groups such as control, T (treated with 63.7 mg/body kg), X (treated with 65.9 mg/body kg) and TX(T=X). Organic solvents was administrated by intraperitoneal injection for 3 days. The contents of protein and CYP in liver microsomes of control group were $16.48{\pm}0.56 mg/m{\ell}$ and $0.744{\pm}0.025$ nmol/mg protein, respectively, and they contents were significantly lower than in derived from treated groups (p<0.01). The activities of PROD and ${\rho}NPH$ were significantly higher in single treated groups than in control and combined group (TX). When Western immunoblotting were carried out with two monoclonal antibodies (MAb 1-98-1 and MAb 2-66-3) which were specific against CYP2B1/2 and CYP2E1, respectively, a strong signal corresponding to CYP2B1/2 was observed in microsomes obtained from rats treated with X and TX. The color density against CYP2E1 was slightly increased in T and TX groups compared with C and X groups. The amounts of urinary hippuric acid in T single treated group was $3.29{\pm}1.97$ g/g creatinine and TX combined group was $2.91{\pm}1.76$ g/g creatinine, but was not significant. However, amount of urinary methy hippuric acid in X single treated group ($1.62{\pm}0.72$ g/g creatinine) was significantly higher than TX combined group ($0.93{\pm} 0.63$ g/g creatinine)(p<0.01). These results suggested that CYP2E1 isozyme might be responsible for the metabolism of T, and CYP2B1/2 isozyme is for X. And also, difference of metabolites level between single and combined group may be speculated that the intermediates of T and X interacted each other in the process of their metabolite formation reaction.