Tumor Induction Time Research Articles

Influence of Repeated Doses of 3-Methylcholanthrene at Fixed Intervals on Breast Cancer in Sprague-Dawley Female Rats.

Summary3-Methylcholanthrene, 0.66 mg/g rat, was administered by gastric tube to female Sprague-Dawley rats, age 50 days. This dose was repeated at 10-day intervals 1, 2, 3, or 4 times. Mammary cancer was observed in 77.3% of rats 90 days after a single dose and in 100% of the animals given 2 or more doses of carcinogen. Maximal acceleration of mean tumor induction time was achieved with 3 doses. The number of tumors observed correlated directly with the number of doses administered, a response which appears to be quantitatively additive.