Investigation of FSH Responsiveness in a Granulosa Cell Line

The follicle stimulating hormone receptor (FSHR) is a g protein‐coupled receptor found in granulosa cells and Sertoli cells in females and males, respectively. FSH binds to its receptor on the surface of granulosa cells leading to proliferation and maturation of follicles towards ovulation. Understanding this pathway is significant because it can lead to developments in regulating fertility. Previously, our lab studied FSHR using an HEK293 cell line stably transfected with FSHR cDNA. More recently we have investigated an immortalized human granulosa cell line (hGrC1) to study FSHR signaling in a more physiologically relevant context. Due to the novelty of the hGrC1 cell line, not much is known about the cells, specifically what stage of follicular development they are most closely related to. Based on previous datafrom our lab regarding FSHR responsiveness, the question arose of whether hGrC1 cells undergo developmental changes in culture. It was hypothesized that this developmental change is analogous to follicular maturation in vivo . The change is significant because FSHR is not present in granulosa cells until later stages of follicular development. hGrC1 cells were grown in culture for a variable number of days before treatment with FSH, after which the presence of phosphorylated CREB and phosphorylated p44 were determined by western blot analysis as measures of FSH dependent signaling. An FSH dependent increase in signaling from both pathways was seen after cells were treated 4 days post‐confluency suggesting that there is a developmental shift leading to more hFSHR protein the longer the cells were grown in culture. This is significant because it suggests that hGrC1 cells mimic granulosa cell differentiation in vitro and may be a viable model for testing both FSHR function as well as understanding the factors driving folliculogenesis.