Comparison of the Hepatic and Renal Effects of 1,4-Dichlorobenzene in the Rat and Mouse

• Published in: Fundamental and applied toxicology Vol. 39; no. 1; pp. 67 - 75
• Main Authors: Lake, Brian G., Cunninghame, Morag E., Price, Roger J.
• Format: Journal Article
• Language: English
• Published: Boston, MA Elsevier Science (USA) 01.09.1997; San Diego, CA Academic Press; New York, NY
• Subjects: Administration, Oral; Animals; Biological and medical sciences; Blotting, Western; Body Weight - drug effects; Carcinogenesis, carcinogens and anticarcinogens; Chemical agents; Chlorobenzenes - administration & dosage; Chlorobenzenes - toxicity; Corn Oil - administration & dosage; Cytochrome P-450 Enzyme System - biosynthesis; DNA Replication - drug effects; Dose-Response Relationship, Drug; Enzyme Induction - drug effects; Insecticides - toxicity; Kidney Neoplasms - chemically induced; Kidney Tubules, Proximal - drug effects; Kidney Tubules, Proximal - pathology; Liver - drug effects; Liver - pathology; Liver Neoplasms, Experimental - chemically induced; Male; Medical sciences; Mice; Microsomes, Liver - drug effects; Microsomes, Liver - enzymology; Organ Size - drug effects; Rats; Rats, Inbred F344; Tumors; Rat; Isozyme; Toxicity; Chemical compound; Liver; Carcinogenesis; Kidney; Ingestion; Dose activity relation; Multiple dose; Enzymatic activity; Chlorocarbon; Mechanism of action; Unspecific monooxygenase; Urinary system disease; Enzyme; Interspecific comparison; Cytochrome P450; Rodentia; Carcinogen; Vertebrata; Mammalia; Mouse; Animal; Digestive diseases; Drug-metabolizing enzyme; Oxidoreductases
• ISSN: 0272-0590; 1095-6832
• DOI: 10.1006/faat.1997.2350

The effects of 1,4-dichlorobenzene (DCB) have been compared in male F344 rats given 0 (corn oil control), 25, 75, 150, and 300 mg/kg DCB and male B6C3F1mice given 0 (corn oil control), 300, and 600 mg/kg DCB by daily oral gavage five days per week for 1, 4, and 13 weeks. The two highest rat and both mouse dose levels were the same as those employed in a NTP bioassay, where DCB produced kidney tumors in male rats and liver tumors in mice. DCB produced significant dose-related increases in relative liver weight in both the rat and the mouse which was associated with, respectively, mild and marked centrilobular hypertrophy. Administration of DCB also produced a sustained induction of microsomal cytochrome P450 content and 7-pentoxyresorufinO-depentylase activity in both species. Western immunoblotting studies demonstrated that DCB induced CYP2B isoenzyme(s) in both rat and mouse liver microsomes. Replicative DNA synthesis was studied by implanting osmotic pumps containing 5-bromo-2′-deoxyuridine in study Weeks 0–1, 3–4, and 12–13. In the rat hepatocyte labeling index values were only increased in animals given 300 mg/kg DCB for 1 week, whereas hepatocyte labeling index values were significantly increased in mice given 300 and 600 mg/kg DCB for 1 and 4 weeks. DCB treatment produced significant increases in rat renal P1/P2proximal tubule cell labeling index values at all time points, whereas little effect was observed in mouse kidney. The observed species difference in DCB-induced liver tumor formation may reflect the greater sensitivity of the mouse to tumor promotion by a CYP2B inducer. For the kidney, the present data provides further evidence that while DCB-induced α2U-globulin nephropathy is associated with a sustained stimulation of cell replication in male rat renal proximal tubule cells, this effect is not observed in the male mouse.