Xenobiotic-metabolizing enzymes in canine mammary tumours

• Published in: The veterinary journal (1997) 2006-09, Vol.172 (2), p.364-368
• Main Authors: Kumaraguruparan, R., Subapriya, R., Balachandran, C., Manohar, B. Murali, Thangadurai, A., Nagini, S.
• Format: Article
• Language: English
• Subjects: Animals; biochemical mechanisms; biochemical pathways; Canine mammary tumour; carcinogenesis; carcinoma; correlation; cytochrome b; cytochrome P-450; Cytochrome P450; dog diseases; Dog Diseases - enzymology; Dogs; DT-diaphorase; enzyme activation; enzyme activity; enzymes; epidemiological studies; Female; females; gamma-glutamyltransferase; Glutathione S-transferase; glutathione transferase; mammary neoplasms (animal); Mammary Neoplasms, Animal - enzymology; metabolic detoxification; metabolic studies; NADPH-diaphorase; pathogenesis; signs and symptoms (animals and humans); xenobiotics; Xenobiotics - pharmacokinetics; γ-Glutamyl transpeptidase
• ISSN: 1090-0233; 1532-2971
• DOI: 10.1016/j.tvjl.2005.05.013

Mammary tumours are the most common neoplasms in female dogs. The present study was designed to evaluate the relationship between different clinical stages with activities of phase I and phase II carcinogen-metabolizing enzymes in canine mammary tumours. The levels of cytochrome P450 and cytochrome b 5 and the activities of glutathione S-transferase (GST), γ-glutamyl transpeptidase (GGT), DT-diaphorase (DTD) and NADPH diaphorase in tumour tissues of 25 bitches was estimated. Enhanced levels of cytochrome P450 and b 5 and phase II enzyme activities were observed in tumour tissues compared to the corresponding uninvolved adjacent tissues. The magnitude of the changes in phase I and phase II enzyme status was, however, more pronounced in stages I and II compared to stages III and IV. The results suggest that the balance between phase I carcinogen activation and phase II detoxification systems may play an important role in canine mammary tumour development.