Effects of dietary cyclopropene fatty acids on estrogen production in strain A/ST mice
Cyclopropene fatty acids (CPFA) found in cottonseed oil (CT) have been shown to reduce production of progesterone, a precursor of estrogen. Estrogenic hormones have been implicated in enhancing growth of mammary tumors. In this study, the effect of dietary cottonseed oil on estrogen production by mature female mice was determined by measuring urinary estrogen using High Performance Liquid Chromatography.At four months of age, five groups of three Strain A/ST female mice were placed on 20% fat diets containing 0, 2.5, 5.0, 10, and 20% cottonseed oil. The remainder of the fat in the experimental diets was corn oil sufficient to provide the balance of the 20% fat content in conjunction with other nutrients of equal percentages in all diets. At five day intervals mice were housed in metabolic cages and twenty-four hour urine samples were collected. Urine was purified on C18 columns and eluted with 1% phosphoric acid: acetonitrile: methanol: (54:35:11). Estrogen was quantified by High Performance Liquid Chromatography using a 250 X 5mm C18 column, hydrocortisone as an internal standard, and variable wavelength recorder set at 242 nm. The level of urinary estrogens after day 35 of the study was lower in all diets containing cottonseed oil. This is in agreement with several authors who have reported instances of physiological abnormalities in mammals which were fed increasing but low levels of dietary cyclopropenes. Since elevated estrogen levels have been identified as a risk for breast cancer, this study examines the relationship between dietary cyclopropenes and estrogen hormone production in strain A/St mice.