Abstract
Investigation of regulation of estradiol production by porcine granulosa cells is hindered by lack of a culture system that consistently produces estradiol for extended periods. Granulosa cells that are characterized by their strong attachment to each other (TB-cells) were compared to cells that lack such attachments (WA-cells) for their responses to FSH, LH, and EGF in androstenedione supplemented medium. TB-cells were separated from WA-cells by filtration and were predominantly aggregates that had a smooth contour on one side of the aggregate. After enzymatic disruption, TB-cells had greater estradiol production than WA-cells when cultured initially, and they maintained this advantage through day 8 when stimulated with FSH or LH. Progesterone production was greater for TB- than WA-cells during initial culture, but by day 8 FSH and LH stimulated progesterone production was similar for these two subpopulations. EGF increased DNA concentrations and decreased production of estradiol and progesterone by similar amounts for each cell type. When TB-and WA-cells were cultured together, estradiol, but not progesterone, production was reduced disproportionately. This indicates that WA-cells or some component of these pools of cells interact with TB-cells to reduce estradiol production. We conclude that TB-cells are primarily from the mural layers within the follicle and are more differentiated at time of collection. The means through which TB-cells sustain FSH stimulated estradiol production in culture and why WA-cells fail to achieve this level of production are unknown.
