title: Effect of delay in administration of 13-cis-retinoic acid on the inhibition of urinary bladder carcinogenesis in the rat.
abstract: The effect of a delay in starting 13-cis-retinoic acid treatment on the inhibition of urinary bladder carcinoma induced by N-butyl-N-(4-hydroxybutyl)nitrosamine was studied in male Fischer 344 rats. Animals received a total p.o. dose of either 1200, 1800 or 2400 mg N-butyl-N-(4-hydroxybutyl)nitrosamine over a period of six weeks. At either one, five, and nine weeks after the last N-butyl-N-(4-hydroxybutyl)nitrosamine intubation, animals were started on a diet supplemented with 13-cis-retinoic acid (240 mg/kg of laboratory chow) or continued on laboratory chow. Animals were killed at one year after the first carcinogen intubation for histological evaluation of the bladder. Feeding of 13-cis-retinoic acid reduced the incidence, average number, and severity of transitional cell carcinomas as well as hyperplasia and cellular atypia. Furthermore, even a nine-week delay in starting the retinoid feeding did not diminish the ability of 13-cis-retinoic acid to inhibit bladder carcinogenesis.
mesh_terms: D000818:Animals; D002085:Butylhydroxybutylnitrosamine / Q000008:administration & dosage; D002295:Carcinoma, Transitional Cell / Q000139:chemically induced / Q000517:prevention & control*; D004305:Dose-Response Relationship, Drug; D008297:Male; D009374:Neoplasms, Experimental / Q000517:prevention & control; D051381:Rats; D011916:Rats, Inbred F344; D013997:Time Factors; D014212:Tretinoin / Q000008:administration & dosage*; D001749:Urinary Bladder Neoplasms / Q000139:chemically induced / Q000517:prevention & control*; D014801:Vitamin A / Q000031:analogs & derivatives*
chemical_list: D014801:Vitamin A; D002085:Butylhydroxybutylnitrosamine; D014212:Tretinoin