Effects of riboflavin deficiency and riboflavin administration on carcinogen-DNA binding.
A study was conducted to assess the effects of riboflavin deficiency and riboflavin supplementation on carcinogen-DNA binding. After 12 wk on a riboflavin-sufficient or a riboflavin-deficient diet male Wistar rats were administered 3H-labelled benzo[a]pyrene (BP) ip. [3H]BP was given either at a uniform dose of 450 muCi/rat irrespective of body weight or at a dose adjusted to body weight. After 17 hr the animals were killed, various organs were dissected and the level of [3H]BP bound to DNA was quantified in organs that are known to be the seats of drug metabolism (i.e. the liver, lungs and intestinal mucosa). In a separate experiment, the effect of riboflavin supplementation on BP-DNA binding was also investigated. When [3H]BP was administered at 450 microCi/rat, BP-DNA binding was markedly increased in the livers and intestinal mucosae of the pair-fed and deficient groups compared with controls. With the administration of [3H]BP adjusted to body weight, no differences in BP-DNA binding between groups were observed in any tissue. However, on administration of riboflavin there was a decrease in the level of [3H]BP bound to DNA in almost all tissues, especially in the lungs, where the reduction was significant. The results suggest that undernutrition/riboflavin deficiency may increase the risk of carcinogenesis by way of an increase in carcinogen binding, which however can be reversed by riboflavin supplementation.
Pangrekar
J
J
Food and Drug Toxicology Research Centre, National Institute of Nutrition, Jamai-Osmania, Hyderabad, India.
Krishnaswamy
K
K
Jagadeesan
V
V
D000818:Animals; D001564:Benzo(a)pyrene / Q000378:metabolism*; D015415:Biomarkers / Q000032:analysis; D015197:Carcinogenicity Tests; D004247:DNA / Q000378:metabolism*; D008297:Male; D009369:Neoplasms / Q000139:chemically induced; D011485:Protein Binding; D051381:Rats; D017208:Rats, Wistar; D012256:Riboflavin / Q000494:pharmacology*; D012257:Riboflavin Deficiency / Q000378:metabolism*; D014018:Tissue Distribution; D015430:Weight Gain / Q000187:drug effects
D015415:Biomarkers; D001564:Benzo(a)pyrene; D004247:DNA; D012256:Riboflavin