Progesterone-mediated effects on gene expression and oocyte-cumulus complex transport in the mouse fallopian tube

The fallopian tube transports the gametes to the fertilization site and delivers the embryo to the uterus at the optimal time for implantation. Progesterone and the classical progesterone receptor (PGR) are known to be involved in regulating both tubal ciliary beating and muscular contractions, possibly involving both genomic and non-genomic actions. To provide more clues on the mechanisms involved, we investigated the effect of progesterone on gene expression in mice fallopian tubes in vitro at early (20 min) and later (2 h, 8 h) time-points using microarray and/or quantitative PCR. In parallel, oocyte cumulus complex transport was investigated in ovulating mice injected with one of the PGR antagonists, Org 31710 or CDB2194. Microarray analyses did not reveal any apparently regulated genes 20 min after progesterone treatment, in agreement with a proposed non-genomic action of progesterone controlling ciliary beating. After 2 h, 11 genes were significantly up-regulated. Analyses by quantitative PCR at 2 h and 8 h showed a consistent up-regulation of endothelin 1 (Edn1) and a down-regulation of its receptor Ednra by progesterone. We also show that treatment with progesterone receptor antagonist before ovulation accelerates the transport of the oocyte cumulus complex. This is the first study showing that progesterone regulates Edn1 and Ednra in the fallopian tube. Together with previous studies on endothelin-mediated effects on muscular contractions in the fallopian tube, the results from this study suggest that endothelin is a mediator of the progesterone-controlled effects on muscular contraction, and eventually gamete transport, in the fallopian tube.

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Bylander A, Gunnarsson L, Shao R, Billig H, Larsson DG