Leukotrienes affect secretory function of ovarian cells in vitro.

The aim of this study was to determine which cells are the source of production and target for leukotriene (LTs) action within the bovine ovary. Luteal (CL, days 14-16 of the oestrous cycle), steroidogenic cells (LSC) and endothelial cells (LEC) of the bovine corpus luteum (CL), and granulosa cells (GC) were isolated enzymatically, cultured in a monolayer and incubated with LTC(4), LTB(4), Azelastine (an antagonist of LTC(4)) or Dapsone (an antagonist of LTB(4)). Then cells were collected for determination of mRNA expression for LT receptors (LTRs) and 5-lipoxygenase (5-LO) by real time RT-PCR, and media were collected for determination of prostaglandin (PG)E(2), F(2α), progesterone (P4; LSC only), endothelin-1 (ET-1; LEC only) and 17-β oestradiol (E2; GC only). The greatest mRNA expression for LTR-II and 5-LO were found in LEC, whereas LTR-I mRNA expression did not differ among cell types. The level of PGE(2) increased after LTs treatment in each type of ovarian cell, excluding LTC(4) treatment in LEC. The secretion of PGF(2α) was also increased by LTs, but decreased after LTB(4) treatment of LSC. In GC cultures, both LTs stimulated E2 secretion; in LEC cultures, LTB(4) stimulated whereas LTC(4) inhibited P4 secretion; in LEC cultures, LTC(4) stimulated but LTB(4) inhibited ET-1 secretion. The results show that LTs are produced locally and are involved in PGs production/secretion in all examined cells (LSC, LEC and GC) of bovine ovary. Leukotriene treatment modulate secretion of E2, by GC, P4 by LSC and ET-1 by LEC, which indicates that LTs are involved in regulation of ovarian secretory functions.