title: Proliferation-stimulating effect of phenacetin on the urothelium and papillary epithelium of rats.
abstract: In the present autoradiographic study, the effect of phenacetin (PH) on the proliferative activity of the urothelium and epithelium lining the renal papilla of rats was tested. The median 3H-thymidine-labeling index (3H-TdR index) of the bladder urothelium of rats daily fed PH for 2 years was twofold increased compared to untreated or initially partially cystectomized rats. The median 3H-TdR index of the papillary epithelium was 2-3 times higher than in untreated controls. The transitional epithelium of the renal pelves showed an approximately 2 times, and the urothelium of the ureters a 3 times increased median 3H-TdR index only when PH administration was combined with an initial one-third resection of the urinary bladder. Since after PH treatment the highest DNA synthesis consistently occurred in all rats with a resected bladder, it can be concluded that partial cystectomy increases the ability of the urothelium and the papillary epithelium to proliferate in response to the drug. The proliferation-stimulating effect of PH can be reconciled with a cocarcinogenic or promoting activity of the drug.
mesh_terms: D000818:Animals; D001345:Autoradiography; D002455:Cell Division / Q000187:drug effects; D004847:Epithelial Cells; D005260:Female; D007679:Kidney Medulla / Q000166:cytology; D007682:Kidney Pelvis / Q000166:cytology; D010615:Phenacetin / Q000494:pharmacology*; D051381:Rats; D011919:Rats, Inbred Strains; D013268:Stimulation, Chemical; D013936:Thymidine; D014513:Ureter / Q000166:cytology; D001743:Urinary Bladder / Q000166:cytology / Q000601:surgery; D014551:Urinary Tract / Q000166:cytology*
chemical_list: D010615:Phenacetin; D013936:Thymidine