title: Effect of three retinoids on tracheal carcinogenesis with N-methyl-N-nitrosourea in hamsters.
abstract: Male Syrian golden hamsters received 12 weekly intratracheal exposures to 0.5% N-methyl-N-nitrosourea with a special catheter. Following exposures, animals were randomized into 4 groups of 63 hamsters and placed on diets of lab meal or meal with 120 mg 13-cis-retinoid acid (CRA)/kg, 327 mg ethyl retinamide (ER)/kg, or 343 mg N-(2-hydroxyethyl)retinamide (HR)/kg for 6 months at which time all hamsters were killed. The observed incidences of tracheal epithelial neoplasms (No. of animals with tumors/total No. of animals) were 10/63 (lab meal), 22/61 (CRA), 24/63 (ER), and 17/62 (HR). The incidence of carcinomas (No. of animals with tumors/total No. of animals) were 4/63 (lab meal), 12/61 (CRA), 12/63 (ER), and 11/62 (HR). The weight loss and mortality relative to those in the group fed the lab meal were significantly in the group fed HR but not in the other retinoid-treated groups.
mesh_terms: D000686:Amyloidosis / Q000139:chemically induced / Q000401:mortality; D000818:Animals; D002277:Carcinoma / Q000139:chemically induced / Q000517:prevention & control*; D006224:Cricetinae; D015474:Isotretinoin; D008297:Male; D008647:Mesocricetus; D008770:Methylnitrosourea; D009374:Neoplasms, Experimental / Q000139:chemically induced / Q000517:prevention & control; D011230:Precancerous Conditions / Q000139:chemically induced / Q000517:prevention & control; D011336:Probability; D014134:Tracheal Neoplasms / Q000139:chemically induced / Q000517:prevention & control*; D014212:Tretinoin / Q000031:analogs & derivatives / Q000494:pharmacology*
chemical_list: C009675:vitamin A acid ethylamide; C022147:N-(2-hydroxyethyl)retinamide; D014212:Tretinoin; D008770:Methylnitrosourea; D015474:Isotretinoin