Effect of aromatase inhibitor (fadrozole) on proliferation, estradiol production and telomerase activity in pig granulosa cells in vitro

The objective of the present work was to study the effect of a nonsteroidal aromatase inhibitor (fadrozole) on proliferation, estradiol production, aromatase expression and telomerase activity (TA) in pig granulosa cells (GC) from small (1–2 mm) and large (5–7 mm) follicles. The cells were treated with fadrozole for 48 h and 72 h in basal and FSH-stimulated conditions. Fadrozole caused a decrease (P < 0.05) of 3H-thymidine incorporation in granulosa cells derived from small (1–2 mm) and large follicles (5–7 mm). The proliferative potential of small-follicle GC was significantly higher (P < 0.01) under all culture conditions. Estradiol production was suppressed (P < 0.01) in both granulosa cell populations cultured in the presence of fadrozole for 48 and 72 h. Fadrozole caused a decrease (P < 0.05) of aromatase gene expression in small-follicle granulosa cell incubated for 72 h and in large-follicle GC after 48 h of culture. Large-follicle GC were characterized by a higher (P < 0.01) level of estradiol production and aromatase gene expression. Telomerase activity decreased (P < 0.05) in large-follicle granulosa cells incubated in the presence of an aromatase inhibitor for 72 h. The TA level in large-follicle granulosa cells was higher (P < 0.01) in comparison to small-follicle GC in all culture conditions after 72 h of incubation. The results of the present study suggest the important role of telomerase in the process of follicular growth and development.