Exp Clin Endocrinol Diabetes 2013; 121 - P41
DOI: 10.1055/s-0033-1336680

Effects of isoflavone exposure on the androgen sensitivity of male Wistar rats

D Mueller 1, T Blei 1, S Soukup 2, C Gerhäuser 3, S Kulling 2, L Lehmann 4, G Vollmer 5, P Diel 1
  • 1German Sports University Cologne, Institute of Cardiovascular Research and Sports Medicine, Department of Molecular and Cellular Sports Medicine, Cologne, Germany
  • 2Max Rubner Institute (MRI), Department of Safety and Quality of Fruit and Vegetables, Karlsruhe, Germany
  • 3German Cancer Research Center (DKFZ), Epigenomics and Cancer Risk Factors Division, Heidelberg, Germany
  • 4University Würzburg, Institute of Food Chemistry, Würzburg, Germany
  • 5Dresden University of Technology, Institute of Zoology, Chair of Molecular Cell Physiology and Endocrinology, Dresden, Germany

There is contradictory data about the consequences of isoflavone (ISO) exposure during development of male and female organisms. Potential impacts on tumor risk, reproduction but also altered susceptibility for metabolic diseases like obesity or diabetes are discussed. An important finding in studies with females was that estrogen sensitivity evidently is affected by lifelong ISO intake. The aim of this study was to investigate whether ISOs also impact on androgen responsiveness in males. Hence we conducted a dose response experiment in male rats starting exposure in utero, maintaining it through adolescence into adulthood. Until sacrification at PND 96 rats received a diet enriched with an ISO extract in different concentrations [IDD (ISO depleted diet); IRD50 (ISO rich diet; 50 mg ISO/kg food); IRD400 (400 mg ISO/kg food)].

To investigate androgen sensitivity we conducted a Hershberger assay. Rats were orchiectomized (ORX) at PND 80. After hormonal decline for 7 days, rats were treated with testosterone propionate [TP (1 mg/kg bw/day)] or vehicle for 10 days.

In ORX rats the treatment with TP generally resulted in an increase of weight of seminal vesicles, prostate and levator ani. Interestingly, rats exposed to ISO showed an increased stimulation of levator ani (by 25%) and seminal vesicle (by 12%) weight by TP if compared to rats grown up on IDD. In TP treated IRD rats bone density of the tibia was also significantly higher than in TP treated IDD animals. TP treatment in ORX IDD and IRD50 rats decreased visceral fat mass by 21%. IRD400 diet was able to reduce it equally without TP stimulation.

In summary, results of this study demonstrate, that exposure over all critical periods of development to ISO results in a decrease of visceral fat mass and prostate weight in ORX animals. Androgen sensitivity of tissues like muscle, seminal vesicles and bone but not prostate was effected by ISO exposure. Underlying molecular mechanisms have to be analyzed in future studies.