Contraception with mifepristone.
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Female↗
Biomedical subjects
K Gemzell
Publications and source records attributed to K Gemzell.
Uterine contractility and interaction between prostaglandins and antiprogestins. Clinical implications.
It is generally believed that progesterone and PGF2 alpha are of major importance in the regulation of uterine contractility. The results summarized herein indicate that progesterone withdrawal is essential for the changes in uterine contractility normally observed during the secretory phase of the menstrual cycle and that the inactivity of the early pregnant uterus is progesterone dependent. Treatment with the antiprogestin RU486 will convert the inactive early pregnant uterus to an active organ and will increase the sensitivity of the myometrium to prostaglandin. These latter effects of antiprogestin have resulted in the development of highly effective, nonsurgical procedures to terminate early pregnancy based on a combined treatment with RU486 and different PG analogues administered orally, vaginally, or intramuscularly. RU486 also has a softening effect on the cervix as demonstrated in late first trimester of pregnancy. This effect may be useful as pretreatment to vacuum aspiration in late first and early second trimester abortion performed by vacuum aspiration or dilatation and curettage. In prostaglandin-induced second trimester abortions, pretreatment with RU486 will significantly reduce the induction-to-abortion interval and the dose of prostaglandin needed.
Abortion, Induced↗
The role of prostaglandins and ovarian hormones in the regulation of human uterine contractility.
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Dinoprostone↗
Regulation of non-pregnant human uterine contractility. Effect of antihormones.
Uterine contractility was recorded on cycle day LH+6 to LH+8 in a control and treatment cycle in 14 healthy non-pregnant volunteers. In the treatment cycle the subjects received either 50 mg of the antiprogestin RU 486 daily for three days or 40 mg of the anti-estrogen tamoxifen daily for two days. The treatment started on day LH+2. During the recording, 2 to 5 micrograms PGF2 alpha was administered into the uterine cavity. The plasma levels of progesterone and estrogen were the same in both the control and treatment cycles. RU 486 caused a significant increase in uterine contractility expressed in Montevideo Units (MU) and a decrease in uterine tonus in comparison with corresponding data obtained in the control cycle. Following treatment with tamoxifen, uterine contractility was lower but the difference was not significant. PGF2 alpha invariably caused a stimulation of uterine contractility. However, treatment with the antihormones did not influence the response. The result of the present study indicates that the change in uterine contractility occurring in the latter part of the menstrual cycle and during menstruation is due to progesterone withdrawal.
Adult↗