Prevention of N-nitrosobis(2-oxopropyl)amine-induced nasal cavity tumors in rats by orchiectomy.

Bilateral orchiectomy, performed 1 week before initiation of weekly sc injections of N-nitrosobis(2-oxopropyl)amine (BOP), prevented induction of hyperplastic and neoplastic lesions in the nasal and paranasal cavities of outbred Wistar-derived MRC rats. However, in BOP-treated rats without surgery or with bilateral vesiculectomy, the incidences of these lesions were 100 and 90%, respectively. Literature review indicates that nasal and paranasal lesions occur predominantly in male domestic animals as well as in human males and suggests a possible hormone dependency of these lesions.