Acute effects of 2-bromopropane and 1,2-dibromopropane on hepatotoxic and immunotoxic parameters in female BALB/c mice

Identification of glutathione conjugates and mercapturic acids of 1,2-dibromopropane in female BALB/c mice by liquid chromatography-electrospray ionization tandem mass spectrometry

Based on recent results that 1,2-dibromopropane (1,2-DBP) causes hepatotoxicity and immunotoxicity in female BALB/c mice as well as a reduction of hepatic glutathione levels, the possible formation of glutathione conjugates and mercapturic acids of 1,2-DBP was investigated in vivo in the present studies. The following four metabolites were identified in the liver at 12 h after treatment with 1,2-DBP, by liquid chromatography-electrospray ionization tandem mass spectrometry (LC-ESI/MS): M1, 2-hydroxypropylglutathione; M2, 2-oxopropylglutathione; M3, N-acetyl-S-(2-hydroxypropyl)-L-cysteine; and M4, N-acetyl-S-(2-oxopropyl)-L-cysteine. Ions of individual conjugates were observed at m/z 366, 364, 222 and 220, respectively. Characteristic product ions at m/z 237, 217, 204 and 202 for the identification of M1, M2, M3 and M4 were observed, respectively. In the sera isolated from the same animals, only mercapturic acids (M3 and M4) were observed by LC-ESI/MS. When female BALB/c mice were treated orally with 1,2-DBP at doses of 150, 300 and 600 mg kg(-1) once for 12 h, the production of glutathione conjugates and mercapturic acids in liver was apparently dose dependent, as were the concentrations of them in sera. When the production of metabolites from 1,2-DBP was investigated in liver following oral treatment with 600 mg kg(-1) 1,2-DBP for 6, 12, 24 and 48 h, metabolite concentrations were greatest at the first time point (6 h). The results explain the authors' previous studies that oral treatment with 1,2-DBP reduces the hepatic content of glutathione.

Role of glutathione conjugation in the hepatotoxicity and immunotoxicity induced by 1-bromopropane in female BALB/c mice

1-Bromopropane (1-BP) is used as a cleaning agent or adhesive solvent in the workplace. In the present study, the hepatotoxic and immunotoxic effects of 1-bromopropane and its conjugation with glutathione (GSH) were investigated in female BALB/c mice. The animals were treated orally with 200, 500 and 1000 mg kg(-1) of 1-BP in corn oil for a dose response study or treated orally with 1000 mg kg(-1) of 1-BP for 6, 12, 24 and 48 h for a time course study. The hepatic and splenic contents of GSH were significantly decreased by 1-BP in a dose-dependent manner. S-propyl GSH was identified in livers following treatment with 1-BP by liquid chromatography-electrospray ionization tandem mass spectrometry. When the production of conjugates from 1-BP was investigated in livers following oral treatment with 1000 mg kg(-1) of 1-BP for 6, 12, 24 and 48 h, the GSH conjugates were detected maximally 6 h after treatment. Treatment of mice with 1-BP increased the serum activity of alanine aminotransferase dose-dependently. The oral 1-BP treatment significantly suppressed the antibody response to a T-dependent antigen and the production of splenic intracellular IL-2 in response to Con A in a dose-dependent manner. The present results suggested that 1-BP could cause hepatotoxicity and immunotoxicity as well as depletion of GSH content due to the formation of GSH conjugates.

Hepatotoxic effect of 1-bromopropane and its conjugation with glutathione in male ICR mice

The hepatotoxic effects of 1-bromopropane (1-BP) and its conjugation with glutathione were investigated in male ICR mice. A single dose (1000 mg/kg, po) of 1-BP in corn oil to mice significantly increased serum activities of alanine aminotransferase and aspartate aminotransferase. Glutathione (GSH) content was dose-dependently reduced in liver homogenates 12 h after 1-BP treatment. In addition, 1-BP treatment dose-dependently increased levels of S-propyl GSH conjugate at 12 h after treatment, as measured by liquid chromatography-electrospray ionization tandem mass spectrometry. The GSH conjugate was maximally increased in liver at 6 h after 1-BP treatment (1000 mg/kg), with a parallel depletion of hepatic GSH content. Finally, 1-BP induced the production of malondialdehyde in liver. The present results suggest that 1-BP might cause hepatotoxicity, including lipid peroxidation via the depletion of GSH, due to the formation of GSH conjugates in male ICR mice.