Aug 2, 2008

Enhanced proliferative response of hepatocytes to combined inhalation and oral exposures to N,N-dimethylformamide in male rats

The Journal of Toxicological Sciences
Hisao OhbayashiHisayoshi Ohta

Abstract

Male Wistar rats were exposed by inhalation to N,N-dimethylformamide (DMF) at 0 (control), 200 or 400 ppm (v/v) for 6 hr/day, 5 days/week and 4 weeks, and each inhalation group received DMF-formulated drinking water at 0, 800, 1,600 or 3,200 ppm (w/w) for 24 hr/day, 7 days/week and 4 weeks. Both the combined inhalation and oral exposures and the single-route exposure through inhalation or ingestion induced centrilobular hypertrophy and single-cell necrosis of hepatocytes, increased plasma levels of alanine aminotransferase (ALT), increased percentage of proliferating cell nuclear antigen (PCNA)-positive hepatocytes without glutathione-S-transferase placental form (GST-P)-positive liver foci, and increased relative liver weight. Those hepatic parameters of the DMF-induced effects were classified into hypertrophic, necrotic and proliferative responses according to the pathological characteristics of affected liver. While magnitudes of the hypertrophic and necrotic responses were linearly increased with an increase in amounts of DMF uptake in the single-route exposure groups, those dose-response relationships tended to level off in the combined-exposure groups. Saturation of the hypertrophic and necrotic responses at high dose lev...Continue Reading

Mentioned in this Paper

Metabolic Process, Cellular
Necrosis
Pulmonary Emphysema
Hypertrophic Cardiomyopathy
Uptake
Hypertrophy
Hepatic
Placenta
Gstp1 protein, rat
Glutathione Measurement

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