n-(2-hydroxyethyl)retinamide and Carcinoma

Syrian hamsters were given in a single dose of N-nitrosobis(2-oxopropyl)-amine (BOP) (40 mg/kg, s.c.) and 1 week later were fed 1 of 4 retinoid types (13-cis-retinoic acid (13-cis-RA), N-ethylretinamide (ERA), 2-hydroxyethylretinamide (OH-ERA), or 4-hydroxyphenylretinamide (PRA)) each at 3 levels (0.05, 0.1, 0.2 mM/kg diet). The pancreatic carcinoma incidence was not influenced significantly by feeding retinoids. The pancreatic adenoma incidence, however, was reduced by feeding each of the retinoids to female hamsters, with the reduction varying with the retinoid fed (13-cis-RA greater than ERA and OH-ERA greater than PRA). In male hamsters increased numbers of pancreatic adenomas were observed after feeding OH-ERA and PRA. Tumors induced in other tissues were reduced by retinoids in females, but not in males. Females fed 13-cis-RA and ERA had a lower incidence of gall bladder polyps, and feeding OH-ERA reduced the liver tumor incidence. Food consumption and serum alkaline phosphatase ans aspartate amino transferase activities were not influenced by BOP or retinoid type or level. Body and pancreas weight were influenced by retinoid level, but the effects were not consistently dose-related.

Topics: Animals; Carcinoma; Cricetinae; Female; Fenretinide; Male; Mesocricetus; Neoplasms, Experimental; Nitrosamines; Pancreatic Neoplasms; Sex Factors; Tretinoin

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.

Topics: Amyloidosis; Animals; Carcinoma; Cricetinae; Isotretinoin; Male; Mesocricetus; Methylnitrosourea; Neoplasms, Experimental; Precancerous Conditions; Probability; Tracheal Neoplasms; Tretinoin