Effects in vivo and in vitro of sex steroids on rat myometrium

Abstract

Spontaneous electrical and mechanical activity was recorded from excised rat myometrium. Treatment with progesterone or estradiol in vitro inhibited electrical and mechanical activity of uterine strips in 15-90 min. Progesterone or estradiol injected into the uterine lumens failed to inhibit activity in 6 hr. Progesterone intramuscularly only or in combination with intraluminal and intraperitoneal administration failed to alter the electrical and mechanical behavior of whole uteri.