Effect of Stage of the Estrous Cycle and Gonadotrophins Upon Luteinization of Porcine Granulosa Cells in Culture

Abstract

Effects of the stage of the estrous cycle in addition to the effects of LH, and FSH added in vitro, upon morphology and progestin secretion of porcine granulosa cell cultures were studied. Cultures of granulosa cells harvested from 7–11 mm follicles of pigs in estrus had some of the same morphological traits as do luteal cells and secreted elevated amounts of progestins. Granulosa cells harvested from smaller follicles of the same ovary, from small follicles of pigs in midluteal phase of the cycle, or from 3–5 mm follicles of 4–6 month old pigs secreted small amounts of progestins. Addition of 0.01–1 µg/ml of porcine LH, 0.1 or 1 µg/ml of porcine FSH at each medium change caused cells harvested from 3–5 mm pig follicles to accumulate lipid droplets and small granules and stimulated progestin secretion 10- to 1000-fold from days 2 to 14 of culture.