Abstract
The aim of the present work was to study the effect of oestrogen receptor inhibitors (ICI 164.384; ICI and cyclofenil; CF) on proliferation, oestradiol synthesis, aromatase expression and telomerase activity (TA) of pig granulosa cells (GC) derived from small (1-2 mm; SF-GC) and large (5-7 mm; LF-GC) follicles. Cells were treated with anioestrogens for 48 h in basic (medium only) as well as FSH-stimulated conditions. Antioestrogens applied individually and in a combination significantly (P<0.01) decreased proliferative potential of LF-GC. Antioestrogens applied in a combination increased (P<0.05-0.01) 17-β oestradiol synthesis in small and large follicle GC. Antioestrogens applied individually and in a combination caused an increase (P<0.01) of aromatase gene expression in FSH-stimulated conditions as well as in basic conditions. Moreover, antioestrogens increased (P<0.05-0.01) TA in basic and in FSH-stimulated conditions. The results of the study indicate the involvement of oestrogen receptor α and β in the control of proliferation, differentiation and telomerase activity in pig GC. Furthermore, telomerase activity does not have to be linked only to pig GC proliferation but may also be involved in the differentiation process.
Highlights
Oestrogens are known to be important factors controlling proliferation and differentiation of granulosa cells (Drummond and Findlay, 1999)
Porcine ovaries were collected from local slaughterhouse and transported to the laboratory in a theromo-cointainer filled with phosphate-buffered saline (PBS) within 30 min
To determine the granulosa cell proliferation potential in vitro, the newly synthesized DNA in cell cultures was measured by incorporation of 3H-thymidine using the technique of TCA precipitation and liquid scintillation counting as we described earlier (Vackova et al, 2003)
Summary
Oestrogens are known to be important factors controlling proliferation and differentiation of granulosa cells (Drummond and Findlay, 1999). Oestrogens exert their role by two subtypes of nuclear receptors: ERα and ERβ. Both subtypes of ER have been localized in mammalian ovary. High amount of ERβ protein and mRNA was detected in the granulosa cells of primary, secondary and antral follicles in rodents (Tremblay et al, 1997; Sar et al, 1999) and humans (Enmark et al, 1997; Pelletier et al, 2000). ERβ was present at all stages of follicular development whereas ERα mRNA and protein were detected only in preovulatory follicles and early corpora lutea
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