N NITROSOBIS (2 OXOPROPYL) AMINE (NBOP), a postulated 3-metabolite of di-n-propyl-nitrosamine, has been found to be a potent carcinogen in different species of animals (Pour et al., 1977a; Rao & Pour, 1978; Pour et al., 1979). In hamsters, a single or repeated s.c. administration of NBOP (Pour et al., 1977a, 1978) is reported to cause a high incidence of pancreatic ductal tumours. Because of th...