Foetal distribution and metabolism of N-nitrosodiethylamine in mice.
In pregnant NMRI mice, low-temperature autoradiography was used to study the distribution of N-14C-nitrosodiethylamine in foetal tissues, and autoradiography with heated tape-sections was used to trace nonvolatile metabolites. Autoradiography with 14C-acetate was used to distinguish the part of the radioactivity which upon the degradation of N-14C-nitrosodiethylamine may be incorporated in the normal metabolism of the tissues. The results indicated that the non-metabolized N-nitrosodiethylamine passed to the foetuses with an even distribution in most foetal tissues on all the studied days of gestation (day 12, 14, 16 and 18). The autoradiographic results further indicated a metabolism of the substance in the mucosa of the foetal bronchial tree and in the foetal liver on day 18 of gestation, but not in earlier stages of pregnancy. This was substantiated by studies in vitro, which showed a marked capacity of the 18 day old foetal lung and liver (in contrast to tissues from 16 day old foetuses) to form 14CO2 from the N-14C-nitrodiethylamine. Since the lung and liver are target tissues for the transplacental carcinogenesis of N-nitrosodiethylamine in NMRI mice, a causal relationship between metabolic ability and carcinogenesis may exist in these tissues.
D000085:Acetates / Q000378:metabolism; D000818:Animals; D001345:Autoradiography; D002250:Carbon Radioisotopes; D004052:Diethylnitrosamine / Q000378:metabolism*; D005260:Female; D005333:Fetus / Q000378:metabolism*; D005865:Gestational Age; D051379:Mice; D008815:Mice, Inbred Strains; D009369:Neoplasms / Q000139:chemically induced; D009602:Nitrosamines / Q000378:metabolism*; D011247:Pregnancy; D014018:Tissue Distribution
D000085:Acetates; D002250:Carbon Radioisotopes; D009602:Nitrosamines; D004052:Diethylnitrosamine