Interleukin-1-mediated regulation of plasminogen activation in pregnant mare serum gonadotropin-primed rat granulosa cells is independent of prostaglandin production.
OBJECTIVE
This study examines the effects of interleukin-1 (IL-1) on plasminogen activator (PA) activity and prostaglandin (PG) E production in pregnant mare serum gonadotropin (PMSG)-primed granulosa cells and the potential involvement of PGE in the regulation of ovarian plasminogen activation.


METHODS
Granulosa cells were obtained from PMSG-primed rat (27-day-old) ovaries and cultured in serum-free conditions for 48 hours in the absence or presence of IL-1 beta (10 ng/mL) with and without transforming growth factor-beta 1 (10 ng/mL). Cellular PA activity was measured through the conversion of plasminogen to plasmin and assay of the plasmin-mediated cleavage of [14C]-labeled globin to acid-soluble products.


RESULTS
Exposure of PMSG-primed granulosa cells to IL-1 resulted in a 30% reduction (P < .05) in PA activity. Addition of hCG (1 IU/mL) to the granulosa cell cultures resulted in a 2.3-fold increase in PA activity, an effect significantly attenuated by co-administration of IL-1. The IL-1-mediated inhibition occurred concurrent with a 6.6-fold increase in the ability of the corresponding conditioned media to inhibit exogenous urokinase activity. This latter inhibitory capacity was the result of a significant increase in plasminogen activator inhibitor type 1 (PAI-1), given its abolition by a polyclonal anti-rat PAI-1 immunoglobulin G. The IL-1-mediated effects on PA/PAI-1 were accompanied by a sevenfold increase in PGE content of the spent culture medium. This response was dose dependent. The IL-1 effects on plasminogen activation and PG production were abolished by the IL-1 receptor antagonist, suggesting specific IL-1 receptor-mediated responses. Indomethacin, an inhibitor of PG biosynthesis, prevented the IL-1-induced increase in PGE accumulation but failed to affect the response of the PA system. Transforming growth factor-beta 1, a known regulator of IL-1 action, significantly attenuated the IL-1-stimulated PGE production but did not interfere with the ability of IL-1 to affect the PA system.


CONCLUSIONS
The present observations suggest a pleiotropic response of PMSG-primed granulosa cells to IL-1, characterized by the induction of PAI-1 concurrent with but independent of PG production. These findings corroborate and extend earlier observations suggesting that IL-1 affects PA activity and PGE production in immature rat ovaries. Moreover, these observations support our contention that IL-1 may play a major regulatory role in the cellular events leading to ovulation and early corpus luteum formation.
Hurwitz
A
A
Department of Obstetrics/Gynecology, Hadassah University Hospital, Mt. Scopus, Jerusalem, Israel.
Finci-Yeheskel
Z
Z
Dushnik
M
M
Milwidsky
A
A
Shimonovitz
S
S
Yagel
S
S
Adashi
E Y
EY
Mayer
M
M
D000818:Animals; D002478:Cells, Cultured; D016895:Culture Media, Serum-Free; D005260:Female; D005341:Fibrinolysin / Q000378:metabolism*; D006064:Gonadotropins, Equine / Q000494:pharmacology*; D006107:Granulosa Cells / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D007213:Indomethacin / Q000494:pharmacology; D007375:Interleukin-1 / Q000494:pharmacology*; D007700:Kinetics; D010053:Ovary / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D017395:Plasminogen Activator Inhibitor 1 / Q000096:biosynthesis; D010960:Plasminogen Activators / Q000378:metabolism*; D011458:Prostaglandins E / Q000096:biosynthesis*; D051381:Rats; D011919:Rats, Inbred Strains; D016212:Transforming Growth Factor beta / Q000494:pharmacology; D014568:Urokinase-Type Plasminogen Activator / Q000037:antagonists & inhibitors
D016895:Culture Media, Serum-Free; D006064:Gonadotropins, Equine; D007375:Interleukin-1; D017395:Plasminogen Activator Inhibitor 1; D011458:Prostaglandins E; D016212:Transforming Growth Factor beta; D010960:Plasminogen Activators; D005341:Fibrinolysin; D014568:Urokinase-Type Plasminogen Activator; D007213:Indomethacin