Avian Granulosa Cell Prostaglandin Secretion is Regulated by Transforming Growth Factor α and β and Does Not Control Plasminogen Activator Activity during Follicular Development1

Abstract

The aim of the present study was to determine the role of transforming factor alpha (TGF alpha) and beta (TGF beta) in the regulation of prostaglandin (PG) secretion, and the relationships between PG and plasminogen activator (PA) activity in hen granulosa cells during ovarian follicular development. Cells from the first (F1), third (F3), and fifth and sixth (F5-6) largest preovulatory follicles were cultured for up to 21 h in the presence of TGF alpha (0.1-10 ng/ml) and/or TGF beta (4-20 ng/ml) or TGF alpha together with a cyclooxygenase inhibitor, indomethacin (0.05-0.5 microM). The release of PG into the incubation medium was determined by RIA. Cell-associated (PAc) and secreted (PAs) PA activities were measured by a fibrinolysis assay and characterized by zymography. Basal PGF secretion from F1, F3, and F5-6 cells was 2.2 +/- 0.3, 2.2 +/- 0.5, and 1.1 +/- 0.3 ng/micrograms DNA, respectively, and was higher than that of PGE. Basal total PA (PAc+PAs) activity from F1, F3, and F5-6 cells was 41 +/- 13,261 +/- 68, and 958 +/- 268 x 10(3) cpm/micrograms DNA, respectively. TGF alpha stimulated PG secretion and PA activity in a dose-dependent manner. The TGF alpha-induced PA activity was predominantly associated with a molecular mass of 30-35 kDa, corresponding to that of urokinase PA. The stimulation of PG secretion by TGF alpha was maximal in F3 and F1 granulosa cells whereas PA activity in the presence of TGF alpha was highest in cells from F5-6 follicles.(ABSTRACT TRUNCATED AT 250 WORDS)

Prostaglandins Mediate the Stimulation of Deoxyribonucleic Acid Synthesis by Transforming Growth Factor α in Hen Granulosa Cells during Ovarian Follicular Development1

“…Consistent with results obtained by us previously [1,17], [ 3 H]thymidine incorporation into DNA (p < 0.01) and PGE (p < 0.01) and PGF (p < 0.01) production in granulosa cells from F1 follicles increased in a dose-dependent manner in response to TGFa (0.1-10 ng/ml). At 1 ng/ml, TGFct significantly stimulated PGE (168%) and PGF (244%) production and DNA synthesis (310%) (Fig.…”

“…Although PG synthesis in granulosa cells during ovarian follicular development has recently been shown to be regulated by a complex interaction of TGFat and TGF3 [17], the physiologic role of these eicosanoids in the control of ovarian cell function by these growth factors is unknown. The present report provides the first demonstration of an involvement of AA metabolites in the regulation of DNA synthesis by growth factors in ovarian cells.…”

“…Although TGFex has been suggested to play an important role in the regulation of ovarian follicular development [1,17], present knowledge of the mechanism by which the growth factor exerts its mitogenic influence on the granulosa cell during folliculogenesis is incomplete. The present studies demonstrate for the first time that PGs, particularly of the E series, may be important mediators of the action of TGFox in the regulation of granulosa cell proliferation during follicular development.…”

“…Previous studies from our laboratory have shown that TGFa increases PG production, plasminogen activator activity, and DNA synthesis in hen granulosa cells in vitro and that the magnitude of these responses is dependent on the stage of follicular development [1,17]. Although the TGFainduced changes in eicosanoid synthesis and activity of plasminogen activator (a protease believed to be involved in extracellular matrix remodeling accompanying granulosa cell proliferation and migration during follicular maturation) are not causally related [17], it is unclear whether PGs play a significant role in the mitogenic response of granulosa cells to TGFa.…”

“…Although the TGFainduced changes in eicosanoid synthesis and activity of plasminogen activator (a protease believed to be involved in extracellular matrix remodeling accompanying granulosa cell proliferation and migration during follicular maturation) are not causally related [17], it is unclear whether PGs play a significant role in the mitogenic response of granulosa cells to TGFa. In the present study, we have examined whether the synthesis and action of PGs contribute to the regulation of DNA synthesis in granulosa cells following TGFat stimulation and, if so, whether this involvement is specific to this class of membrane lipid metabolites.…”