The influence of vitamin A on the susceptibility of the rat lung to 3-methylcholanthrene.
The susceptibility of rats to pulmonary carcinogens is increased in the absence of vitamin A intake even when considerable amounts (0.4 nmole/mg) of vitamin A are stored in the liver and deficiency symptoms are absent. This was demonstrated in studies on the induction of metaplastic lung nodules by intratracheally administered 3-methylcholanthrene. Only moderate amounts of all-trans-retinyl acetate in the diet (7.6 nmole/g of diet) were required to prevent the development of this state of enhanced susceptibility. A further increase in intake of retinoids (by intragastric administration of either all-trans-retinyl acetate or 13-cis-retinoic acid) provided no additional protection against the effects of carcinogen.
D000818:Animals; D005260:Female; D008168:Lung / Q000187:drug effects / Q000473:pathology; D008175:Lung Neoplasms / Q000139:chemically induced* / Q000473:pathology / Q000517:prevention & control; D008748:Methylcholanthrene; D009374:Neoplasms, Experimental / Q000139:chemically induced / Q000517:prevention & control; D051381:Rats; D014212:Tretinoin / Q000627:therapeutic use; D014801:Vitamin A / Q000494:pharmacology*
D014801:Vitamin A; D008748:Methylcholanthrene; D014212:Tretinoin