BioProject

Ovulation is induced by the preovulatory surge of luteinizing hormone (LH) that acts on the ovary and triggers the rupture of the preovulatory ovarian follicle by stimulating proteolysis and apoptosis in the follicle wall, causing the release of the mature oocyte. More...

Ovulation is induced by the preovulatory surge of luteinizing hormone (LH) that acts on the ovary and triggers the rupture of the preovulatory ovarian follicle by stimulating proteolysis and apoptosis in the follicle wall, causing the release of the mature oocyte. In mammals, the pro-inflammatory cytokine tumor necrosis factor α (TNFα) and prostaglandin F2α (PGF2α) are known to be involved in the control of ovulation but their role mediating the pro-ovulatory actions of LH has not been established. Here we show that Lh induces PGF2α synthesis through its stimulation of Tnfα production in trout, a primitive teleost fish. Importantly, trout recombinant Tnfα (rTnfα) and PGF2α recapitulate the stimulatory in vitro effects of salmon Lh (sLh) on contraction, proteolysis and loss of cell viability in the preovulatory follicle wall and, finally, ovulation. Furthermore, all pro-ovulatory actions of sLh are blocked by inhibition of Tnfα secretion or PG synthesis and those of rTnfα are blocked by PG synthesis inhibitors. Therefore, we provide evidence that the Tnfα–dependent increase in PGF2α production is necessary for the pro-ovulatory actions of Lh in a teleost fish. The results from this study shed light onto the mechanisms underlying the pro-ovulatory actions of LH in vertebrates and may prove important in clinical assessments of female infertility. Overall design: Preovulatory follicles from brook trout from four different females (n = 4) were isolated and incubated in the absence or presence of salmon LH. Total RNA of control and LH-treated preovulatory follicles from each of the four females was analyzed. Less...