단백식이 조건을 달리하여 성장시킨 흰쥐에 Bromobenzene 투여가 간손상에 미치는 영향

신중규(Joong-Kyu Shin),채순님(Soon-Nim Chae),윤종국(Chong-Guk Yoon) 한국식품영양과학회 1994 한국식품영양과학회지 Vol.23 No.6

식이성 단백질이 bromobenzene에 의한 간손상에 어떠한 영향을 미치는 지를 검토코저 흰쥐를 저(LP : casein 7%) 및 고(HP : casein 20%)단백식이로 1개월간 성장시킨 뒤 bromobenzene을 투여한 다음, 간무게, 혈청 alanineaminotransferase (ALT) 활성을 측정하여 간손상 정도를 두 군간에 비교하였다. 아울러 이에 대한 기전을 구명하는 일환으로 간조직 중 aniline hydroxylase (AH) 활성과 glutathione (CSH) 함량 및 이의 포합효소인 glutathione S-transferase (CST) 활성을 측정하였다. Bromobenzene 투여로 인한 대조군에 대한 간중량 및 혈청 ALT 활성 증가율은 LP군이 HP군 보다 높았다. 이때 간 AH 활성 증가율은 HP군 보다 LP군이 높았으나, 간 CSH 및 CST 활성은 LP군 보다 HP군이 높게 나타났다. 이상 실험결과를 종합하여 볼 때 bromobenzene에 의한 간독성을 식이 중 단백질 함량 감소에 영향을 받으며, 이는 LP군이 HP군 보다 bromobenzene 투여로 인한 간 AH 활성은 증가되나 bromobenzene 해독에 관여하는 간 glutathione 함량과 CSH 활성의 감소에 기인되기 때문인 것으로 생각된다. To evaluate an effect of dietary protein on the liver damage, the bromobenzene was intraperitoneally injected to the rats fed a low or high protein diet and then the liver weight per body weight and serum levels of alanine aminotransferase (ALT) activities were determined to demonstrate the differences in liver damage between the groups fed low or high protein diet. Hepatic aniline hydroxylase (AH), glutathione (CSH) content and glutathione S-transferase (CST) activity were also determined to clarify causes of liver damage between the two groups. Increases of liver weight per body weight and serum ALT activities were higher in bromobenzene treated rats fed low protein diet than those fed high protein diet. The increasing rate of hepatic AH activity was higher in bromobenzene-treated rats fed low protein diet than that in those fed high protein diet. Furthermore, hepatic glutathione contents and CST activities in bromobenzene-treated rats were higher in rats fed high protein diet than those fed low protein diet. In case of control group, the hepatic glutathione content and CST activity were also higher in rats fed high protein diet than those fed low protein diet.

조선업 용접작업장의 공기중 입자상물질 및 구성성분에 관한 연구

강용선 ( Yong Seon Kang ),신중규 ( Joong Kyu Shin ),이송권 ( Song Kwon Lee ),윤충식 ( Chung Sik Yoon ),임무혁 ( Moo Hyuk Lim ),박만철 ( Man Chul Park ),심상효 ( Sang Hyo Sim ) 한국산업위생학회 2007 한국산업보건학회지 Vol.17 No.3

This research was performed to evaluate the airborne personal concentration of hazardouse materials during the process of ship construction and surveyed from May 23 to June 30, 2007 in Kyungnam West Distirct, Korea. The subject was 94 ship construction workers exposed to welding fume and respirable particulate. The airborne concentrations of those were compared to Permissible Exposure Limit(PEL) from the Ministry of Labor in Korea. The airborne concentration of 23 samples(48.9%) of welding fumes was less than 5㎎/㎥, that of 16 (34.0%) was between 5 and 10㎎/㎥, and that of 8 (17.0%) was greater than 10㎎/㎥. The airborne concentration of 27 (57.4%) of respirable particulate masses was less than 5㎎/㎥ and the othere are greater than 5 ㎎/㎥. The welding fumes were identified containing the heavy metasl such as Fe, Mn, Zn, Mg, Ca, and Cu. The respirable particulates has similiar tendency with welding fumes in the component of heavy metals. But the concentration of Ca, Cu, Cr, and Ni turned out to be higher in welding fumes. Twenty (42.6%) of the 47 samples of welding fumes were exceeded PEL. In the heavy metals in welding fumes, ten (21.3%) of the 47 samples of Mn were exceeded PEL. Based on the results, the higher airborne hazardous materials were still exposed to wokers in ship construction process. It is suggested that the appropriate engineering control be applied to minimize the exposed cocnetration in ship building processes.

흰쥐에 있어서 Toluene 대사에 미치는 주ㆍ야 시차의 영향

류종일(Jong-Ihl Ryu),윤종국(Chong-Guk Yoon),신중규(Joong-Kyu Shin) 대한의생명과학회 1999 Biomedical Science Letters Vol.5 No.1

주ㆍ야 (day, night phase) 시차에 따른 toluene 대사를 검토할 목적으로 흰쥐에 50% toluene (olive oil과 toluene의 동량혼합액)을 체중 100 g 당 0.2 ㎖씩 밤 12시, 낮 12시에 각각 투여한 다음 각각 8시간 후에 처치하여, 다음과 같은 결과를 얻었다. 간 microsomal aniline hydroxylase 활성은 night phase군이 day phase군 보다 대조군 및 toluene 투여군 모두 높게 나타났으며, cytosol의 benzylalcohol dehydrogenase (BADH) 활성은 night phase군과 day phase군 간에 별다른 차이를 볼 수 없었으나, toluene 투여시에는 night phase군이 day phas군 보다 효소의 활성도가 오히려 억제되었다. 또한 간 조직의 benzaldehyde dehydrogenase (BALDH) 활성은 night phase군이 day phase군 보다 다소 높게 나타나는 경향을 보였으며, toluene 투여시에는 night phase군에서는 대조군 보다 오히려 감소되었으나 day phase 군에서는 높게 나타나는 경향을 보였다. 그리고 in vitro 시험에서 benzylalcohol 및 benzaldehyde가 BADH 및 BALDH 활성을 억제시킴이 관찰되었다. 요 중 hippuric acid 함량은 대조군 및 toluene 투여군 모두 night phase군과 day phase군 간에는 별다른 차이를 볼 수가 없었다. 한편 toluene 투여로 인한 체중 당 간 무게 및 혈청 xanthine oxidase 활성 증가율은 night phase군이 day phase군 보다 높게 나타났다. 이상 실험결과를 종합해 볼 때 요 중 hippuric acid 함량이 주ㆍ야 시차에 따라 별다른 차이가 없는데도 불구하고 toluene으로부터 benzylalcohl이 및 benzaldehyde 생성률이 day phase군 보다 night phase군이 높게 나타남으로서 toluene 대사산물에 의한 간 손상 정도가 day phase군 보다 night phase군이 높게 나타난 것으로 사료 되어진다. To investigate the effect of the circadian variations on the toluene metabolism, 50% toluene in olive oil (0.2 ㎖/100 g 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. Each group of animals was sacrificed at 8 hr after last injection of toluene. Hepatic microsomal aniline hydroxylase activity was more increased in control rats of night phase than those of day phase. On the other hand, the activities of hepatic benzylalcohol dehydrogenase in control rats of night phase showed the similiar value with that in those of day phase and in case of toluene treatment, these enzyme activities in rats of night phase were rather more decreased than those of day phase. Furthermore, hepatic benzaldehyde dehydrogenase activities were more or less higher in the control rats of night phase than those of day phase and by toluene treatment, enzyme activities of rats of night phase were somewhat decreased than those of day phase. In vitro, benzylalcohol or benzaldehyde inhibited the activities of benzylalcohol or aldehyde dehydrogenase prepared from the rats liver supernatant. There were no differences in urinary hippuric acid contents between the night phase and day phase both in the control and toluene treated group. The increasing rate of liver weight per body weight (%), serum xanthine oxidase activities were higher in rats of night phase than in those of day phase by toluene treatment. In conclusion, these results indicate that the producing rate of benzylalcohol and benzaldehyde from toluene may be higher in rats of night phase than those of day phase.

흰쥐의 성별이 Toluene 대사효소 활성 및 요 중 마뇨산 농도에 미치는 영향

윤종국(Chong-Guk Yoon),채순님(Soon-Nim Chae),신중규(Joong-Kyu Shin) 한국독성학회 1999 Toxicological Research Vol.15 No.2

Toluene (50% in olive oil) was intraperitoneally given three times at 0.2 ml/100 g body weight at interval of one day to male and female rats. The concentration of urinary hippuric acid was markedly higher in male rat than in female rats. Concomitantly, the activities of toluene metabolizing enzymes (hepatic aniline hydroxylase, aminopyrine demethylase, benzylalcohol dehydrogenase and benzaldehyde dehydrogenase) were also higher in male than in female rats. Furthermore, all the hepatic aniline hydroxylase, aminopyrine demethylase activities and benzaldehyde dehydrogenase activities were significantly decreased in castrated rats as compared to in be male control rats. In conclusion, these results suggested that testosterone level may affected upon the metabolism of toluene in rats.

식이성 단백질 함량에 따른 흰쥐에 사염화탄소 투여가 Xanthine Oxidase활성에 미치는 영향

윤종국(Chong-Guk Yoon),이상일(Sang-Il Lee),신중규(Joong-Kyu Shin) 한국식품영양과학회 1991 한국식품영양과학회지 Vol.20 No.6

CCl₄에 의한 간손상의 병태생리와 xanthine oxidase 효소의 관련 여부를 검토하는 일환으로 흰쥐를 저단백(7% casein) 및 고단백식이 (20% casein)으로 성장시킨 다음 50% CCl₄ (v/v in olive oil)를 복강내에 주사후 간손상 정도를 비교함과 동시에 간조직의 free radical 생성계 및 해독계에 관련된 효소 활성과 간 및 혈청중 xanthine oxidase 활성을 측정하여 이들 성적을 상호비교 검토하였다. 또한 xanthine oxidase가 CCl₄에 의한 간손상에 관련되는지를 확인할 목적으로 allopurinol 전처리한 다음 CCl₄를 투여한 xanthine oxidase 결핍모델에서 간손상 정도를 CCl₄투여군과 비교검토하는 한편, HP군에서 LP군보다 간 및 혈청 xanthine oxidase 활성이 증가되는 원인을 구명하는 일환으로 actinomycin D 효과와 본 효소를 간조직 중에서 정제한 후 반응속도면에서 검토하였다.<br/> HP군에서 CCl₄투여로 인한 간무게, 혈장 alanine aminotransferase(ALT)활성 증가율과 간 ALT 및 단백질 함량 감소율이 LP군 보다 높았으며, 병리조직학적 검사소견에서도 HP군에서 LP군 보다 간손상 정도가 높게 나타남이 확인되었다. 이러한 실험모델에서 HP군의 대조군 및 CCl₄투여군 모두 LP군의 대조군 및 CCl₄투여군 보다 간과 혈청 xanthine oxidase 활성이 대체적으로 증가되었으며 간 aniline hydroxylase활성 및 glutathione함량 역시 HP군이 LP군 보다 높게 나타났다. 그러나 CCl₄투여군에 있어서 간 aniline hydroxylase와 glutathione S-transferase활성은 두 군간에 별다른 차이를 관찰할 수 없었다. 그리고 allopurinol을 전처리한 후 CCl₄ 투여시에 혈장 ALT 및 체중당 간무게는 CCl₄만 투여한 실험군 보다 감소되었다. 한편 간조직을 정제한 xanthine oxidase활성에 있어서 대조군 및 CCl₄투여군 모두 HP군이 LP군보다 본 효소의 활성이 높게 나타났으며, Vmax역시 HP군이 LP군 보다 높았다. LP군에 있어서 Km치는 대조군과 CCl₄투여군 간에 별다른 차이를 볼 수 없었으나 HP군의 Km치는 CCl₄투여군이 대조군 보다 감소되었다. 그리고 actinomycin D 전처리후 CCl₄를 투여한 경우에는 간 및 혈청 xanthine oxidase 활성 감소율이 HP에서 LP군 보다 더 높게 나타났다.<br/> 이상 성적을 종합해 볼 때 실험동물에 식이성단백질 함량을 높일때 CCl₄로 인한 간손상이 심하게 나타남과 동시에 간 및 혈청 xanthine oxidase 활성이 증가되는 점과 xanthine oxidase 활성 억제제인 allopurinol이 CCl₄의 간독성을 억제시키는 현상은 CCl₄대사에 약물대사효소 이외 xanthine oxidase도 관여할 것이라는 것을 시사해 주고 있다. To evaluate an effect of liver xanthine oxidase on the induction of liver damage, carbon tetrachloride (CCl₄) was intraperitoneally injected twice at 0.l㎖/100g body weight to the rats fed a low (LP) or high protein diet (HP) while the control group fed LP or HP received only olive oil. The changing rate of liver xanthine oxidase activity was compared with that of a free radical generating enzyme, liver aniline hydroxylase and a scavenging enzyme, glutathione S-transferase activity between the rats fed a LP and those fed HP, and the two groups treated with CCl₄. Concomitantly, the degree of liver damage which could be considered as the parameter for CCl₄ metabolism in case of CCl₄-intoxicated animal was observed in the present experimental conditions and the effect of allopurinol, xanthine oxidase inhibitor, on the CCl₄-toxicity of rats liver was also demonstrated. On the other hand, the comparative effect of actinomycin D on the liver and serum xanthine oxidase of CCl₄-treated rats fed HP with that of those fed LP and the kinetics of purified liver enzyme from the liver of CCl₄-treated rats fed HP was also compared with that of those fed LP to clarify the differences of xanthine oxidase activity between two groups. The increasing rate of liver weight / body wt, serum levels of ALT and the decreasing rate of hepatic ALT activity and protein contents to each control group were higher in CCl₄-treated rats fed HP than those fed LP. Histopathological findings also showed more severe damage in CCl₄-treated rats fed HP than those fed LP. Under the animal models as indentified by the present data herein, the liver xanthine oxidase activity was higher in CCl₄-treated rats fed HP than those fed LP, and the control group fed HP also showed the much higher activity xanthine oxidase than that fed LP, whereas there were no differences in the activity of hepatic aniline hydroxylase and glutathione S-transferase between the two group treated with CCl₄.<br/> Although the hepatic aniline hydroxylase activity was somewhat higher in the rats fed HP than those fed LP, the increasing rate of liver xanthine oxidase to the rats fed LP was higher in those fed HP than that of liver aniline hydroxylase. The degree of liver damage identified such as liver weight and serum ALT activity was less in the CC1₄-treated rats pretreated with allopurinol. These results suggest that even a system at which xanthine oxidase acts as well as the drug metabolizing enzyme may influence the accelation of CCl₄ metabolism. In addition, the purified liver xanthine oxidase from CCl₄-treated rats fed HP showed decreased Km value when compared to its control group. The Km value of liver xanthine oxidase of CCl₄-treated rats fed LP showed a similar Km value with its control group. Furthermore, the decreasing rate of liver and serum xanthine oxidase activity in CCl₄-treated rats pretreated with actinomycin D to the CCl₄-treated rats was higher in rats fed HP than in those fed LP. These results suggest that the induction of xanthine oxidase in CCl₄-treated rats fed HP may be greater than in those fed LP.

흰쥐에 Toluene과 Alcohol의 병행투여가 Toluene 대사 효소활성에 미치는 영향

윤종국(Chong-Guk Yoon),전재현(Jai-Hyun Jeon),신중규(Joong-Kyu Shin) 한국식품영양과학회 1996 한국식품영양과학회지 Vol.25 No.6

흰쥐를 대조군과 체중 100g 당 ethanol 0.3ml를 1일 1회 4일간 복강내로 투여한 실험군, 체중 100g 당 toluene 0.3ml를 1일 1회 4일간 복강내로 투여한 실험군 및 ethanol 투여 2시간 후 toluene을 투여한 군으로 나누어 실험을 행하여 다음과 같은 결과를 얻었다. Alcohol 투여군, toluene 투여군 모두 간 microsomal aniline hydroxylase(AH) 및 aminopyrine demethylase(AD) 활성도가 대조군 보다 유의한 증가를 보였다. Toluene과 ethanol의 병행군은 toluene 투여군 보다 AH 및 AD 활성도가 다소 낮게 나타나는 경향을 보였다. 간조직 중 benzylalcohol dehydrogenase 활성도 역시 alcohol 및 toluene 투여군 모두 대조군에 비하여 높게 나타났으며 toluene과 alcohol의 병행투여군은 toluene 투여군 보다 본 효소 활성도가 다소 낮게 나타나는 경향을 보였다. 한편 간조직 중 benzaldehyde dehydrogenase 활성도는 alcohol 및 toluene 투여군 모두 대조군에 비하여 증가되는 경향을 보였으며 alcohol과 toluene의 병행 투여군은 toluene 투여군 보다 유의한 감소를 보였다. 또한 간조직 중 xanthine oxidase 활성도는 alcohol과 toluene 병행 투여군이 toluene 투여군 보다 유의하게 증가되었다. 이상 실험성적을 종합해 볼 때 alcohol의 전처치는 toluene 대사 효소 활성도를 억제시켜 toluene대사에 영향을 미칠 것으로 생각된다. To elucidate the effect of acute ethanol pretreatment on some toluene metabolizing enzyme activities, rats were divided into 4groups: control, alcohol-treated, toluene-treated, rat's and toluene-treated rats pretreated with ethanol. The alcohol or toluene-treated rats showed the significantly increased activities of hepatic aniline hydroxylase(AH) and aminopyrine demethylase(AD) compared to the control group. And the toluene-treated rats pretreated with ethanol showed somewhat decreased tendency of these enzyme activities compared to only toluene-treated rats. Liver benzylalcohol or aldehyde dehydrogenase activities were higher in alcohol or toluene-treated rats than those of the control group. The toluene-treated rats showed the decreased tendency of benzylalcohol dehydrogenase activities by the pretreatment of alcohol. Furthermore, toluene treated-rats showed the markedly decreased activity of benzaldehyde dehydrogenase by the ethanol pretreat-ment. On the other hand, hepatic xanthine oxidase activity in toluene-treated animals pretreated with ethanol was significantly higher than those of the toluene alone-treated rats. These results indicate that the combination of ethanol with toluene treatment for a short period of time possibly results in decreased activity of some toluene metabolizing enzymes in rats.

흰쥐에 있어서 Toluene대사에 미치는 주.야 시차의 영향

류종일,윤종국,신중규 THE KOREAN SOCIETY FOR BIOMEDICAL LABORATORY SCIEN 1999 Journal of biomedical laboratory sciences Vol.5 No.1

주·야 (day, night phase) 시차에 따른 toluene 대사를 검토할 목적으로 흰쥐에 50% toluene (olive oil과 toluene의 동량혼합액)을 체중 100 g 당 0.2 ml씩 밤 12시, 낮 12시에 각각 투여한 다음 각각 8시간 후에 처치하여, 다음과 같은 결과를 얻었다. 간 microsomal aniline hydroxylase 활성은 night phase군이 day phase군 보다 대조군 및 toluene투여군 모두 높게 나타났으며, cytosol의 benzylalcohol dehydrogenase (BADH) 활성은 night phase군과 day phase군 간에 별다른 차이를 볼 수 없었으나, toluene 투여시에는 night phase군이 day phase군 보다 효소의 활성도가 오히려 억제되었다. 또한 간 조직의 benzaldehyde dehydrogenase (BALDH) 활성은 night phase군이 day phase군 보다 다소 높게 나타나는 경향을 보였으며, toluene 투여시에는 night phase군에서는 대조군 보다 오히려 감소되었으나 day phase군에서는 높게 나타나는 경향을 보였다. 그리고 in vitro 시험에서 benzylalcohol 및 benzaldehyde가 BADH 및 BALDH 활성을 억제시킴이 관찰되었다. 요 중 hippuric acid 함량은 대조군 및 toluene 투여군 모두 night phase군과 day phase군 간에는 별다른 차이를 볼 수가 없었다. 한편 toluene투여로 인한 체중 당간 무게 및 혈청 xanthine oxidase 활성 증가율은 night phase군이 day phase군 보다 높게 나타났다. 이상 실험결과를 종합해 볼 때 요 중 hippuric acid 함량이 주·야 시차에 따라 별다른 차이가 없는데도 불구하고 toluene으로부터 benzylalcohol 및 benzaldehyde 생성률이 day phase군 보다 night phase군이 높게 나타남으로서 toluene 대사산물에 의한 간 손상 정도가 day phase군 보다 night phase군이 높게 나타난 것으로 사료되어진다. To investigate the effect of the circadian variations on the toluene metabolism, 50% toluene in olive oil (0.2ml/100 g 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. Each group of animals was sacrificed at 8 hr after last injection of toluene. Hepatic microsomal aniline hydroxylase activity was more increased in control rats of night phase than those of day phase. On the other hand, the activities of hepatic benzylalcohol dehydrogenase in control rats of night phase showed the similiar value with that in those of day phase and in case of toluene treatment, these enzyme activities in rats of night phase were rather more decreased than those of day phase. Furthermore, hepatic benzaldehyde dehydrogenase activities were more or less higher in the control rats of night phase than those of day phase and by toluene treatment, enzyme activities of rats of night phase were somewhat decreased than those of day phase. In vitro, benzylalcohol or benzaldehyde inhibited the activities of benzylalcohol or aldehyde dehydrogenase prepared from the rats liver supernatant. There were no differences in urinary hippuric acid contents between the night phase and day phase both in the control and toluene treated group. The increasing rate of liver weight per body weight (%), serum xanthine oxidase activities were higher in rats of night phase than in those of day phase by toluene treatment. In conclusion, these results indicate that the producing rate of benzylalcohol and benzaldehyde from toluene may be higher in rats of night phase than those of day phase.

一部再修生들의 行態와 心身健康狀態와의 關係

申重圭,李誠 國 대한보건협회 1984 대한보건연구 Vol.10 No.2

A survey was carried out on physical and mental unidentified complaints of 544 male repeaters who regularly attend a lecture in a preparatory school using a questionaire from March 10 to May 10, 1984. The unidentified complaints were evaluated by means of their behavior patterns such as sleeping condition, smoking, drinking, use of drugs and meal patterns. The purpose of this investigation is to determine the relationship between their behavior patterns and level of unidentified complaints. The results obtaind are summarized as follows: The level of unidentified complaints was classified into 3 groups: A group(under 5 items), B group (6~11 items), C group(12 items and over). Average number of unidentified complaints accounted for 3.7±1.3 items for A, 8.6±1.6 items for B, 12.6±0.9 items for C, and 8.1±3.1 items for the total. The higher frequency rate of complaints revealed 84.0% of "fatigue", 79.0% of "eye-strain", 64.3% of "headache", in physical complaints, and 73.7% of "depression", 67.5% of "anxiety", 55.7% of "inability to concentration", 51.1% of "irritability", in mental complaints. There was statistically significant between unidentified complaints and behavior patterns such as sleeping condition, sleeping hours, and use of drugs (p<0.01). Those who slept uncomfortable(27.8%), 8 hours and over(18.9%), and using a sedative(27.6%) had relatively more complaints in C group. The relationship between unidentified complaints and meal patterns also was statistically significant (p<0.01). Those who had frequent lack of breakfast and lunch, irregural dinner(18.7%) had relatively more complaints in C group. The better physical-mental health status appears to be affected by the better eating behavior. In summarizing, the result of the survey clearly indicates that there would be significant relationship between behavior patterns and physical-mental health status on repeaters.

공무원 및 교직원의 HBsAg 및 Anti-HBs 양성율과 전이 효소 활성치와의 관련성

신중규 대한보건협회 1988 대한보건연구 Vol.14 No.1

This study was carried out in Taegu city for the some public officials and school personnel population to find out the prevalence of HBsAg and Anti-HBs among population, and particulary the relationship between the presence of HBsAg and liver function tests (AST, ALT) from April to July 1986. The HBsAg was detected in 91 among 878 with positive rate of 10.4%. The positive rate of HBsAg was higher in male (11.9%) than in female (7.3%). The positive rate of Anti-HBs was 33.5% and it was higher in male (34.3%) than in female (32.0%). Elevated AST (>40IU/l) and ALT (>35IU/1) were higher in HBsAg positives (respectively 11.0%, 12.1%) than that of Anti-HBs positives (respectively 6.7%, 7.1%) and both negatives (respectively 4.6%, 5.2%). The mean values of AST and ALT in HBsAg and Anti-HBs positives showed higher than that of both negatives.

Effect of Cyclohexane and Xylene Mixture Treatment on the Liver Damage in Rats

신중규 THE KOREAN SOCIETY FOR BIOMEDICAL LABORATORY SCIEN 2003 Journal of biomedical laboratory sciences Vol.9 No.2

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.