Effect of tobacco extract and N′-nitrosonornicotine on the carcinogen metabolising enzymes under different dietary vitamin B status

• Published in: Cancer letters Vol. 52; no. 2; pp. 153 - 159
• Main Authors: Ammigan, N., Nair, U.J., Amonkar, A.J., Bhide, S.V.
• Format: Journal Article
• Language: English
• Published: Shannon Elsevier Ireland Ltd 16.07.1990; Elsevier
• Subjects: Animals; Ascorbic Acid - metabolism; Biological and medical sciences; Carcinogens - metabolism; Cytochrome P-450 Enzyme System - metabolism; diets; Glutathione - metabolism; Liver - enzymology; Liver - metabolism; Lung - enzymology; Medical sciences; metabolising enzymes; N'-nitrosonornicotine; Nicotiana; Nitrosamines - pharmacology; Plant Extracts; Plants, Toxic; Rats; Rats, Inbred Strains; tobacco extract; Tobacco, tobacco smoking; Toxicology; Vitamin A - metabolism; vitamin B; Vitamin B Complex - physiology; Vitamin B Deficiency - physiopathology; xenobiotics; metabolising enzymes; vitamin B; tobacco extract; N′-nitrosonornicotine; Rat; Enzyme; Liver; Lung; Rodentia; Extract; B-Vitamins; Metabolism; Feeding; Carcinogen; Vertebrata; Tobacco; Mammalia; Animal; Xenobiotic
• ISSN: 0304-3835; 1872-7980
• DOI: 10.1016/0304-3835(90)90258-Y

Studies were carried out to evaluate the changes in the phase I and II enzymes of xenobiotic metabolism, on treatment with tobacco extract (TE) and a tobacco specific carcinogen, N′-nitrosonornicotine (NNN) in Sprague-Dawley rats maintained on vitamin B complex sufficient and deficient semi-synthetic diets. Both TE and NNN significantly increased the hepatic and pulmonary phase I enzymes in the vitamin B sufficient (SB +) and deficient (SB −) animals. However, the percent increase in enzyme activities was drastically higher in the SB − treated group as compared to those in the SB +-treated group. On the other hand, TE and NNN significantly depressed the liver and lung glutathione (GSH) level and glutathione S-transferase (GST) activity in the SB − animals, while the opposite effect was observed in the SB +-treated animals. Furthermore, both the treatments depleted the hepatic pool of vitamin A, with a concurrent increase in that of vitamin C in SB + and SB − groups.