Ciliary beat frequency controlled by oestradiol and progesterone during ovarian cycle in guinea‐pig Fallopian tube

The ciliary beat frequency (CBF) of guinea-pig fimbria during the ovarian cycle was measured by video microscopy using a high-speed camera (500 Hz). In the follicular phase, with increasing concentrations of β-oestradiol ([βE2]) and a low concentration of progesterone ([PRG]), CBF increased from 13.5 to 16 Hz. In the ovulatory phase, with further increase of [βE2], CBF decreased gradually from 16 to 13.5 Hz. In the early luteal phase, with low [PRG] and [βE2], CBF increased to ∼17 Hz; however, in the middle luteal phase, with increasing [PRG], CBF decreased (∼12 Hz), and in the late luteal phase, with decreasing [PRG], CBF increased to ∼15 Hz. Then, in the resting phase, with low [βE2] and [PRG], CBF decreased immediately to ∼14 Hz. The CBF of the fimbria was measured in guinea-pigs treated with β-oestradiol benzoate (βE2B) or medroxyprogesterone (mPRG). A low dose of βE2B increased CBF to ∼14.5 Hz, whereas a high dose decreased it to ∼11 Hz. A βE2 receptor blocker, ICI-182,780, abolished the βE2B-induced CBF changes and maintained CBF at ∼12.0 Hz. Medroxyprogesterone decreased CBF to ∼12.5 Hz, and mifepristone (a PRG receptor blocker) abolished the mPRG-induced CBF decrease and maintained CBF at ∼15 Hz. The addition of both blockers increased CBF to ∼18 Hz, suggesting that activation of βE2 or PRG receptors decreases the CBF of the fimbria. In conclusion, a moderate [βE2] increase maintains a high CBF (15.5 Hz) in the follicular phase, and then further [βE2] increase decreases CBF to 13.5 Hz in the ovulatory phase. In the early and late luteal phase, low [βE2] and [PRG] increase CBF to 17 and 15 Hz, respectively, and in the middle luteal phase a high [PRG] decreases CBF (to ∼12 Hz). Thus, the CBF of the fimbria was controlled by signals via βE2 and PRG receptors in guinea-pigs.