BACKGROUND: A reliable means of menstrual suppression would greatly improve the quality of life for @entity1 . Information is lacking on the direct endometrial effects and appropriate dosages of new antiprogestins that may be useful for this purpose. METHODS: The current work evaluated three different systems in macaque monkeys. First, the range of doses of two relatively new antiprogestins, ZK 137 316 and ZK 230 211, that would block @entity1420 action directly on the endometrium in artificially cycled, spayed @entity2608 ; second, the direct endometrial effects of ZK 230 211, a type III antiprogestin; and third, investigation of whether endometrial-suppressive doses administered chronically to intact, cycling monkeys could be used for reversible, menstrual suppression. RESULTS: The results in naturally cycling animals showed that ZK 137 316 blocked menstruation in all animals, but doses of 0.05 mg/kg blocked ovulation in 55.5% of animals and doses of 0.1 mg/kg blocked ovulation in 66.6% of the animals. However, all doses of ZK 230 211 that blocked menstruation also blocked ovulation. All @entity1420 antagonist (PA)-treated animals, regardless of dose, maintained normal follicular phase concentrations of @entity53 and returned to normal menstrual cyclicity within 15--41 days post-treatment. Therefore ZK 137 316, depending on dose, can allow ovulation but block menstruation, while ZK 230 211, a much more potent PA, blocks both ovulation and menstruation at all effective doses. Both PAs block unopposed oestrogenic action on the endometrium through their antiproliferative effects. CONCLUSIONS: Reversible @entity4999 can be achieved with these two PAs, and they can protect the endometrium from the effects of unopposed @entity2931 whether or not ovulation is blocked. Chronic, low dose PA treatment may provide a new option for @entity1 who wish to suppress their menstrual periods.

Reversible suppression of menstruation with @entity1420 antagonists in XXXX .

@entity1 :: ('9606', 'Species') :: ['women'] @entity1420 :: ('MESH:D011374', 'Chemical') :: ['progesterone'] @entity2931 :: ('CHEBI:50114', 'Chemical') :: ['oestrogen'] @entity53 :: ('MESH:D004958', 'Chemical') :: ['oestradiol'] @entity2608 :: ('9544', 'Species') :: ['rhesus macaques'] @entity4999 :: ('MESH:C537962', 'Disease') :: ['amenorrhoea']
@entity2608 :: (9544,Species) :: ['rhesus macaques']
