Ethylnitrosourea (ENU) was injected intravenously into Sprague–Dawley rats on day 15 of
gestation at doses of 0, 2.50, 6.25 and 10.00 mg/kg. The resulting 1980 progeny were
observed for up to 24 months in a life-time study (900 rats) or for periods of 171–325 days in
a serial sacrifice study (1080 rats). The rats in both studies were randomized into three
groups, one exposed to a radiofrequency, one sham-exposed and one cage control. Since
no effects of the radiofrequency were observed on the ENU-induced tumors, the exposure …