Promotional effect of two-generation exposure to a high-fat diet on prostate carcinogenesis in ACI/Seg rats.

Epidemiological studies have shown an association between a high-fat diet and a high mortality rate from breast, colon, and prostate cancer. However, the promotional effect of a high-fat diet on experimental carcinogenesis has not been fully established for the prostate. In this study, the effect on prostatic carcinogenesis of two-generation exposure to a high-fat diet was investigated using ACI/Seg rats, a strain with high incidence of spontaneous prostate cancer. A high-fat diet (20% corn oil) or a low-fat diet (5% corn oil) was given to mother rats during pregnancy and the newborn male rats were fed the same diets for 60 or 100 weeks after weaning. At 100 weeks, atypical hyperplasia and adenocarcinoma of the prostate were respectively found in 73.3% (11/15) and 20.0% (3/15) of the high-fat diet group and in 20.0% (3/15) and 0% (0/15) of the low-fat diet group. There was a significant increase of atypical hyperplasia in the high-fat diet group (P < 0.05). The serum concentrations of sex hormones and the prostatic proliferative activity as measured by flow cytometry or bromodeoxyuridine labeling were not significantly affected by diet. These results showed that feeding a high-fat diet before conception and from the beginning of organogenesis had a marked promotional effect on the early stage of prostate carcinogenesis in rats.