Two New Antiprogestins Suppress Periods In Animal Model.

2001 AUG 23 - (NewsRx Network) -- Two new types of antiprogestins that can suppress menstruation and could end the monthly misery many women suffer have passed their first tests in animals, scientists report.

Studies in rhesus macaque monkeys show that that one drug - ZK 137 316 - can, depending on dose, allow ovulation but block menstruation, while the other - ZK 230 211 - blocks both ovulation and menstruation. Of great importance, both drugs block the effects of estrogen on the lining of the uterus, thus preventing the potentially dangerous build-up of endometrial cells caused by the action of unopposed estrogen ("Reversible suppression of menstruation with progesterone antagonists in rhesus macaques," Human Reproduction, July 27, 2001 ;16(8):1562-1574).

The studies have been carried out in Dr. Robert Brenner's laboratory in the Division of Reproductive Sciences at Oregon Regional Primate Research Center. Rhesus macaque monkeys were used because they are one of the only animals that regularly menstruates and the mechanism in the brain, ovary, and uterus controlling their periods is identical to that of humans. According to Brenner, senior scientist with the Oregon Center, the results should therefore be directly applicable to women.

"A reliable means of menstrual suppression would greatly improve the quality of life for women. The modem woman is accustomed to having control over her reproductive functions and menstruation is one function that many women would like to control. It is possible to use the oral contraceptive pill without the pill-free interval for this purpose, but not all women can tolerate the Pill and there are some health conditions that proscribe its use," Brenner said.

"Our goal in these ...