title: Reduced prevalence and growth rate of urethane-induced lung adenomas in ageing adult strain A mice.
abstract: Following administration of 1.0 mg of urethane/g body wt the average diameter and prevalence of lung adenomas in adult strain. A mice were found to be progressively smaller in animals of progressively greater age at initiation of treatment. Reduction of tumor diameters below detectibility in animals in the older treatment groups could not account for the concurrent reduction in prevalence. Explanations for the observed data in ageing animals based on considerations of reduced immunocompetence or on decreased urethane metabolism or distribution were also considered insufficient. Possible mechanisms for the observed data are discussed.
mesh_terms: D000236:Adenoma / Q000139:chemically induced* / Q000473:pathology; D000375:Aging; D000818:Animals; D008175:Lung Neoplasms / Q000139:chemically induced* / Q000473:pathology; D008297:Male; D051379:Mice; D008805:Mice, Inbred A; D009374:Neoplasms, Experimental / Q000139:chemically induced / Q000473:pathology; D009929:Organ Size; D012890:Sleep / Q000187:drug effects; D014520:Urethane / Q000494:pharmacology / Q000633:toxicity*
chemical_list: D014520:Urethane