Estrogenic Activity of 3-4 Benzpyrene. ∗

Abstract

Cook and Dodds 1 reported that 3 of the carcinogenic hydrocarbons were estrogenic. The carcinogenic and estrogenic effects were not quantitatively or temporally related. A causal relationship is a matter for speculation. Of these 3 estrogenic carcinogens 3-4 benzpyrene has been the most extensively experimented with. Cook and Dodds injected 100 mg of the carcinogenic hydrocarbon in oil subcutaneously into each of 10 rats. Three of the 10 rats receiving 3-4 benzpyrene had positive vaginal smears for 150 hours.

Carminati 2 reported that 3-4 benzpyrene was not estrogenic. He used the same dose as Cook and Dodds for 2 rats, and various smaller doses for 9 other rats.

We injected 31 mg of 3-4 benzpyrene in 0.75 cc of lard subcutaneously into each of 4 mice standardized according to Palmer's 3 method. In 48 hours 3 had positive vaginal smears. On the fifth day the fourth mouse had plus-minus reaction. On the sixth day all were negative, and remained so. Twenty spayed but not standardized mice were injected subcutaneously with 4 mg of 3-4 benzpyrene in lard. They did not develop estrus. Much of the injection mass was present in the 2 mice dying without tumor and a moderate amount present in those developing tumors so the estrogenic amount must lie between 31 and 4 mg.

One of the 4 animals receiving 31 mg of 3-4 benzpyrene died in the third week. A second animal died at 2½ months. Neither of these had tumors. One month after being injected 2 animals developed tumors at the site of injection. One of these animals was the one that did not go into estrus. The other was not in estrus when the tumor began.