The effects of molybdenum and tungsten supplementations on reproductive hormones of female rats fed AIN-76A or lab chow

Abstract

A previous study has demonstrated that in ppm Mo in drinking water significantly (p<O.OF)) prolonged the estrous cycle and inhibited N-nitroso-N-methylurea-induced mammary carcinogenesis in female rats. In the present study, 3-week old female rats were divided into 8 groups of IR animals each. Groups 1-5 were fed ad libitum for 4, 10, or 20 weeks ATN-76A-based diets containing 0.025, 2.0, 20.0, 0.025 or 2.0 ppm Mo; while Groups 6-8 were fed Ralston Purina Lab Chow-based diets containing 2.0, 20.0 or 2.0 ppm Mo, respectively. The diets for groups 4, 5 and 8 were also supplemented with 150 ppm tungsten (W). There were no statistically significant (p>0.05) differences in body weight gain among groups 1-8. Estrous cycles were followed by vaginal smear. At week 20, the estrous cycle of group 3 was significantly (p<0.05) longer than that of group 4. Animals were sacrificed at the estrous phase of the cycle. Plasma estradiol concentrations ranged from 36.8 to 55.0 pa/ml for week 10, and 27.5 to 51.6 pg/ml for week 20. Estradiol levels of the AIN-76A-fed groups were generally greater than those of the Lab Chow-fed groups. The mean estradiol value of group 3 or 5 was significantly (p<0.05) higher than that of group 7 or 8, respectively. Plasma follicle stimulating-hormone (FSH) concentrations ranaed from 3.05 to 3.65 ng/ml for week 10, and 3.21 to 3.97 ng/ml for week 20. There were no significant (p>0.05) differences in FSH levels of rats fed either ATN-76A- or Lab Chow-based diets for both weeks 10 and 20. The estradiol and FSH levels appear to be influenced by the differences in the diets. No significant (p>0.05) differences in uterine weights among rats fed either AIN-76A- or Lab Chow-based diets.