Myometrial maxi-K channel beta1 subunit modulation during pregnancy and after 17beta-estradiol stimulation.

Myometrial maxi-K channels are modulated by beta subunits. We aimed to determine whether beta subunits are modulated to affect uterine excitability during gestation. RNase protection analyses revealed that mouse beta1 subunit transcripts are regulated during gestation with peak expression at day 14 of pregnancy. Immunohistochemical analysis indicates an increase of this subunit during gestation. Upregulation of the beta1 transcript occurs with 4-day exposure to 17beta-estradiol but not progesterone, and acute estradiol exposure has no effect on beta1 transcript expression. These findings verify that beta1 subunit transcript is regulated in mouse myometrium during gestation and estrogens may contribute to this increase.