The effect of β‐carotene on BP‐induced respiratory tract tumors in hamsters

Abstract

The modifying effect of β‐carotene on benzo[a]pyrene (BP)‐induced tumors of the respiratory tract was investigated in Syrian hamsters. Groups of hamsters were fed a semisynthetic diet supplemented with either no or 56 mg/kg β‐carotene. Respiratory tract tumors were induced by intratracheal instillation of BP attached to ferric oxide. The β‐carotene and vitamin A contents of the liver were increased in the high β‐carotene group, but the serum β‐carotene levels were very low when compared with those commonly observed in humans. β‐Carotene supplementation did not affect the tumor response of the respiratory tract. Neither the incidence and severity of preneoplastic changes were influenced. However, there was a statistically significant inverse relationship between serum retinol content and the presence of respiratory tract tumors in survivors, regardless of the dietary treatment.