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 ([βE 2 ]) and a low concentration of progesterone ([PRG]), CBF increased from 13.5 to 16 Hz. In the ovulatory phase, with further increase of [βE 2 ], CBF decreased gradually from 16 to 13.5 Hz. In the early luteal phase, with low [PRG] and [βE 2 ], 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 [βE 2 ] and [PRG], CBF decreased immediately to ∼14 Hz. The CBF of the fimbria was measured in guinea‐pigs treated with β‐oestradiol benzoate (βE 2 B) or medroxyprogesterone (mPRG). A low dose of βE 2 B increased CBF to ∼14.5 Hz, whereas a high dose decreased it to ∼11 Hz. A βE 2 receptor blocker, ICI‐182,780, abolished the βE 2 B‐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 βE 2 or PRG receptors decreases the CBF of the fimbria. In conclusion, a moderate [βE 2 ] increase maintains a high CBF (15.5 Hz) in the follicular phase, and then further [βE 2 ] increase decreases CBF to 13.5 Hz in the ovulatory phase. In the early and late luteal phase, low [βE 2 ] 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 βE 2 and PRG receptors in guinea‐pigs.