The aim of the study was to determine whether consumption of diets containing different fat (rapeseed oil or lard-rich), supplemented with a high level of cholesterol (3% w/w) and/or vitamin E (500 mg/kg of diet) for 6 weeks influenced 17beta-hydroxysteroid dehydrogenase (17β-HSD) type 3 activity (measured in vitro), testosterone (Tt) content in testes and plasma testosterone (Tp) concentration (measured by ELISA and RIA, respectively) in male rats. 17β-HSD activity was shown to depend on dietary fat type. Supplementation of vitamin E influenced Tt value, whereas none of the investigated dietary factors had effects on Tp. Significant differences between the investigated factors were observed only for groups fed rapeseed oil-rich diets with marked increases of Tt and Tp in rats fed vitamin E-rich diet.
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The aims of the study were to compare the in vitro effects of daidzein or 17ß-estradiol (E2) on: 1) progesterone (P4) secretion by luteinized granulosa cells harvested from large porcine follicles, as well as 2) estrogen receptor and ß (ER and ERß) mRNA and protein expression in the cells. In addition, the effect of daidzein on E2 secretion and viability of the granulosa cells was examined. We found that basal and gonadotropin-stimulated P4 secretion were inhibited in granulosa cells cultured in the presence of daidzein either for 24 or 48 hours. In contrast to daidzein, E2 reduced P4 secretion only during 24-hour cell cultures increasing it during longer cultures. Daidzein did not affect E2 secretion by granulosa cells. The expression of ER and ERß mRNA, as well as ERß protein, was up-regulated by daidzein but unaffected by E2. To conclude, the soy estrogen daidzein acts directly on the porcine ovary to decrease progesterone production and to increase expression of ERß mRNA and protein. Daidzein actions in porcine luteinized granulosa cells differ from those of estradiol and it may suggest disadvantageous effects of the phytoestrogen on reproductive processes in females.