Embryopathic action of ethylnitrosourea in the male mouse manifest in the first generation

Offspring from paternal mice treated with E.N.U. (80 mg/kg/ip) incurred an increased incidence of pre- and post-weaning mortality. Fifty five per cent of females conceived in the month following treatment became tumour bearing animals compared with 39 per cent in the controls, the difference being significant (p less than 0.05, binomial analysis). Forty two per cent of female offspring conceived in the month presented reticuloses, compared with 21 per cent of the controls (p less than 0.01, binomial analysis). A highly significant difference also occurred in the incidence of vascular tumours in male and female offspring produced by mice exposed to E.N.U. compared with those from concurrent untreated controls (p less than 0.001 binomial analysis). This is the first report of a statistically significant increase in neoplasia in offspring produced by a male mouse exposed to E.N.U.