Abstract A37: Differential response of LH and hCG on ovarian granulosa cells

Abstract

Abstract LH hyperstimulation has been linked to conditions like PCOD and granulosa cell tumor. Chapekar had established a model of ovarian tumorigenesis by bilateral ovariectomy and splenic transplantation of ovaries, resulting in sustained LH levels because of absence of feedback inhibition. An in vitro model of the same phenomenon has resulted in goat ovarian granulosa cell line after exposure of primary granulosa cells to LH. In this study, we have exposed primary ovarian granulosa cells to either hCG or LH in a sustained manner (4 weeks). We observed a marked difference in the morphology and growth pattern between the LH treated, hCG treated and untreated cells. LH treated cells were transparent, spindle shaped with elongated cell extensions. hCG treated cells were distinctly polygonal with shorter cell extensions, while untreated cells were smaller with fewer extensions and lesser in number as compared to the hormone treated cells. Functional characterization of the granulosa cells was done by estimation of progesterone in supernatant by ELISA. Levels of progesterone were similar in all three subsets in primary culture. The untreated and hCG exposed cells showed markedly reduced cell proliferation after the fourth week of exposure while LH treated cells were proliferating rapidly even after 4 weeks. There were marked differences in downstream signaling molecule cAMP after short term (5 days) and long term stimulation (two weeks) with LH and hCG. Intacellular cAMP was assessed by ELISA. On prolonged exposure to LH and hCG, level of cAMP was significantly higher in hCG treated cultures as compared to LH treated cultures. Elevated cAMP levels on hCG stimulation is known to promote apoptosis in cells. This in vitro model system is suitable to study the effect of sustained hormonal stimulation on granulosa cells and can help in understanding the role of LH and hCG in etiology and pathogenesis of granulosa cell tumor which constitutes 1–2% of ovarian tumors. Citation Information: Cancer Prev Res 2010;3(1 Suppl):A37.