High fat diet increases the weight of rat ventral prostate

Background. Understanding the mechanisms by which diet influences the prost ate may eventually lead to novel approaches for preventing prostate cancer. The objective of this research is to examine the impact of dietary fat, vi tamin D, and genistein on prostate weight, serum and intraprostatic androge n levels, and the expression of several androgen-response genes. Methods. Sprague-Dawley rats were fed, beginning at 21 days of age, for 1 o r 3 months of experimental diets with high saturated fat (32.2% calories fr om fat), low saturated fat (3.6% calories from fat), genistein plus (20 mg/ kg), genistein deficient, vitamin D surplus (4,000 U/kg), or vitamin D defi cient. The body weight, food intake, the weights of the ventral prostate an d dorsolateral prostate, and the levels of testosterone and dihydrotestoste rone (DHT) in the serum and in the prostate were determined. The expression of androgen-response genes was characterized by Northern blot analysis. Results. The pilot experiments showed that high dietary fat appeared to con sistently increase the weight of the ventral prostate, while vitamin D or g enistein did not have a consistent effect on prostate weight. Further analy sis confirmed that the ventral prostate is 15% (P<0.001) heavier in the rat on a high fat diet as compared to a low fat diet. Dietary fat had no signi ficant influence on the levels of serum and intraprostatic androgens and th e expression of androgen-response genes. Conclusions. Our results suggested that the ventral prostate weight of the rat is increased without affecting the androgen axis by feeding the animals with high fat diet beginning at 21 days of age. This observation is potent ially important since epidemiological data suggest that saturated fat consu mption is a major risk factor associated with prostate cancer incidence rat e. Prostate 49: 1-8, 2001. (C) 2001 Wiley-Liss, Inc.