Caffeine inhibits development of benign mammary gland tumors in carcinogen-treated female Sprague-Dawley rats.

The purpose of this study was to assess the influence of caffeine on the incidence of benign mammary tumors in carcinogen (DMBA) treated female Sprague-Dawley rats. Four different animal models were used in these studies, i.e., the administration of DMBA to: [1] 55 day old virgin rats; [2] 53 day old ovariectomized, estrogen treated virgin rats; [3] 135 day old virgin rats and [4] 135 day old parous rats. A high incidence of benign mammary fibroadenomas was observed in each of the four animal models. In addition, in the estrogen treated ovariectomized animals, a high incidence of secretory mammary gland cysts was observed. Caffeine (500 mg/L drinking water) was administered daily throughout the study commencing 3-31 days after carcinogen treatment. Caffeine treatment significantly (P less than 0.05 to P less than 0.001) reduced the incidence of benign mammary fibroadenomas in the 55 day old virgin rat model (P less than 0.01), in the 53 day old estrogen treated ovariectomized virgin rat model (P less than 0.05 to P less than 0.001) and in the 135 day old virgin rat model (P less than 0.05). The number of benign mammary fibroadenomas was reduced by caffeine in the 135 day old parous rat model but this reduction was not significant (P less than 0.10). In addition, in the estrogen treated ovariectomized virgin rat model, caffeine significantly (P less than 0.05 to P less than 0.001) reduced the incidence of mammary gland cysts. Caffeine treatment either increased or had no significant effect on body weight gains, depending upon the animal model.(ABSTRACT TRUNCATED AT 250 WORDS)