Department of Integrative Biology, University of Guelph, Ont. N1G 2W1, Canada.
Department of Integrative Biology, University of Guelph, Ont. N1G 2W1, Canada.
Gen Comp Endocrinol. 2019 Nov 1;283:113228. doi: 10.1016/j.ygcen.2019.113228. Epub 2019 Jul 23.
Prostaglandins (PGs) are a class of fatty acid-derived hormones that play an essential role in the regulation of ovulation of teleosts. This study investigated the various isoforms of ovarian PG receptors in the zebrafish ovary and their role in ovulation. Using real time qPCR, six PG receptor isoforms (ptger1a, ptger1b, ptger2a, ptger4a, ptger4b, and ptgfr) were shown to be expressed in the ovary. Only the PG receptor isoform ptger4b was upregulated at the time of ovulation in vivo, or following treatment in vivo with Ovaprim, which contains a gonadotropin releasing hormone analogue and a dopamine receptor antagonist and stimulates ovulation. Treatment of full-grown follicles with the maturation-inducing hormone 17α,20β-dihydroxy-4-pregnen-3-one (17,20βP) in vitro also induced expression of EP4b mRNA. Females ovulate in vivo after injection with Ovaprim, or injection with Ovaprim and inhibitors of EP1 (ONO-8130) or EP2 (TG4-155) function; they do not ovulate when injected with Ovaprim and an EP4 inhibitor (GW237368x). These findings suggest that the EP4 receptor, in particular the EP4b isoform, is essential for ovulation.
前列腺素（PGs）是一类脂肪酸衍生的激素，在调节硬骨鱼排卵中发挥着重要作用。本研究调查了斑马鱼卵巢中各种卵巢 PG 受体同工型及其在排卵中的作用。使用实时 qPCR，显示了六种 PG 受体同工型（ptger1a、ptger1b、ptger2a、ptger4a、ptger4b 和 ptgfr）在卵巢中表达。只有 PG 受体同工型 ptger4b 在体内排卵时或体内用 Ovaprim 处理（含有促性腺激素释放激素类似物和多巴胺受体拮抗剂并刺激排卵）时上调。用成熟诱导激素 17α，20β-二羟基-4-孕烯-3-酮（17,20βP）在体外处理完全成熟的卵泡也诱导 EP4b mRNA 的表达。雌性在体内注射 Ovaprim 后排卵，或注射 Ovaprim 和 EP1（ONO-8130）或 EP2（TG4-155）抑制剂的功能；当注射 Ovaprim 和 EP4 抑制剂（GW237368x）时，它们不排卵。这些发现表明 EP4 受体，特别是 EP4b 同工型，对于排卵是必需的。
