Testing potential effect of environmental endocrine disruptors in cow milk on reproductive index in female rats.

OBJECTIVE To study the effect of endocrine disruptor chemicals in cow milk on female reproductive system. METHODS A two-generation reproduction was conducted according to U. S. FDA standard. Milk was fed in special bottle to Wistar rats of both sexes through two successive generations (F0 and F1) in the milk group while artificial milk was fed to rats in the control group. Twenty-four rats of each sex were mated in each group. Measurements were made according to this guideline. RESULTS Reproductive parameters in the milk group such as fertility index, gestation index, weights of uterus and ovary, days of vaginal opening, estrous cycles, histological morphological changes were comparable to those in the control group. However, the means of body weight had some differences. The body weight gains increased significantly in the milk-treated group in F1 and F2 generation compared with those in the control group. The concentration of insulin-like growth factor-1 (IGF-1) in blood in the milk group was comparable to that in the control group, but the standard deviation changed greatly in the milk-treated rats. CONCLUSION Endocrine disruptor chemicals in milk have no severe effects on the female reproductive system.