Agradecimentos: The authors thank Mr. Luiz Roberto Falleiros, Jr., for technical assistance and all the researchers from the Laboratory of Microscopy and of IBILCE/UNES. They are also grateful to Dr. Rejane Maira Góes for providing all necessary facilities to carry out the ELISA analysis; Dr. Lilian Castiglioni by statistical analysis support, Professor Robin Camargo and Dr. Peter James Harris for the English language revision of this paper, and to Dr. Ellen C R Leonel Ver menos

Abstract: Vegetable oils are frequently used as a vehicle in the administration of lipophilic drugs in animal tests. However, the composition of these oils may interfere with the results. One alternative to reduce this potential bias is the use of mineral oil, which is not supposed to interfere in the physiology of experimental models, since this oil is considered to be innocous. The present study shows for the first time the effects of the oral administration of corn and mineral on the prostate, demonstrating their interference in homeostasis and revealing their potential to act as endocrine disruptors. Mineral oil treatment increased the expression of AR and ERa and serum estradiol concentrations, while corn oil increased the expression of positive cells for both types of estrogen receptors. The variation in the expression of these hormone receptors resulted in morphological changes in the prostate Ver menos