Effects of Ethanol and Phenobarbital on Hemoglobin Adducts Formation in Rats Exposed to Direct Black 38 / 예방의학회지

OBJECTIVES: To evaluate the effects on the formation of benzidine-hemoglobin, and benzidine metabolite-hemoglobin adducts, caused by pretreatment with the known xenobiotic metabolism effectors, ethanol and phenobarbital, in rats administered Direct Black 38 dye. METHODS: The experimental rats were divided into three groups: a control group, an ethanol group and a phenobarbital group. Rats were pretreated with ethanol (1g/kg) or phenobarbital (80mg/kg) 24 hours prior to the oral administration of Direct Black 38 (0.5mmol/kg), with the control group being administered the same amount of distilled water. Blood samples were obtained from the vena cava of 5 rats from each group prior to, and at 30 min, 3 h, 6 h, 9 h, 12 h, 24 h, 48 h, 72 h, 96 h, and 144 h following the oral administration of Direct Black 38. Directly after sampling the blood was separated into hemoglobin and plasma, with the adducts being converted into aromatic amines by basic hydrolysis. Hydrolyzed benzidiene, monoacetylbenzidine and 4-aminobiphenyl were analyzed by reverse-phase liquid chromatography with an electrochemical detector. The quantitative amount of the metabolites was expressed by the hemoglobin binding index (HBI). RESULTS: In the ethanol group, benzidine-, monoacetylben-zidine-, and 4-aminobiphenyl-HBI were increased to a greater extent than those in the control group. These results were attributed to the ethanol inducing N-hydroxylation, which is related to the formation of the hemoglobin adduct. In the phenobarbital group, all the HBIs, with the exception of the benzidine-HBI, were increased to a greater extent than those of the control group. These results were attributed to the phenobarbital inducing N-hydroxylation related to the formation of the hemoglobin adduct. The N-acetylation ratio was only increased with the phenobarbital pretreatment due to the lower benzidine-HBI of the phenobarbital group compared to those of the control and ethanol groups. The N-acetylation ratios for all groups were higher than 1 for the duration of the experimental period. Although the azo reduction was unaffected by the ethanol, it was inhibited by the phenobarbital. The ratio of the benzidine-HBI in the phenobarbital group was lower than those of the ethanol the control groups for the entire experiment. CONCLUSION: Our results indicate that both ethanol and phenobarbital increase the formation of adducts by the induction of N-hydroxylation, but also induced N-acetylation. Phenobarbital decreased the formation of benzidine-HBI due to the decrease of the azo reduction. These results suggest that the effects of ethanol and phenobarbital need to be considered in the biochemical monitoring of Direct Black 38.

The Metabolism of Benzidine-based Dye Direct Black 38 in the Isolated Perfused Rat Liver / 대한산업의학회지

Direct Black 38, a kind of benzidine-based azo dye, is widely used as a dye for fabric, leather, cotton, cellulosic material, paper, wool, silk, and so on. Benzidine-based azo dyes are proven as a mutagen and linked to bladder cancer. In 1978, Natonal Institute for Occupational Safety and Health recommended that three widely used benzidine-based dyes (Direct Black 38, Direct Blue 6, and Direct Brown 95) should be treated as carcinogens. In this experiment, metabolism of the benzidine-based dye. Direct Black 38 was examined by using an isolated liver perfusion system. To measure the metbolites of Direct Black 38,/ 8.0 micrometer, 30.5 micrometer and 63,3 micrometer of Direct Black 38 was added into the recirculating perfusate of the isolated perfused rat liver. Samples were collected at 0, 10, 20, 30, 60, 90. 120 minute. They were treated with sep-pak and methanol, and the metabohtes were detected and quantified with high performance liquid chromatography (HPLC). Residual non-reactive dye in the perfusate and liver was reduced to benzidine and then analyzed by HPLC. Detected metabolites of ?Direct