Intrauterine administration of CDB-2914 (Ulipristal) suppresses the endometrium of rhesus macaques
Related Experiment Video
Updated: Jun 15, 2026
Methods for Studying Uterine Contributions to Pregnancy Establishment in an Ovariectomized Mouse Model
Published on: April 7, 2023
Robert M Brenner1, Ov D Slayden, Anita Nath
1Division of Reproductive Sciences, Oregon National Primate Research Center, OHSU, Beaverton, OR 97006, USA. brennerr@ohsu.edu
Background:
Ulipristal (UPA; CDB-2914) is a progesterone receptor modulator with contraceptive potential. To test its effects when delivered by an intrauterine system (IUS), we prepared control and UPA-filled IUS and evaluated their effects in rhesus macaques.
Study Design:
Short lengths of Silastic tubing either empty (n=3) or containing UPA (n=5) were inserted into the uteri of 8 ovariectomized macaques. Animals were cycled by sequential treatment with estradiol and progesterone. After 3.5 cycles, the uterus was removed.
Results:
During treatment, animals with an empty IUS menstruated for a mean total of 11.66+/-0.88 days, while UPA-IUS treated animals bled for only 1+/-0.45 days. Indices of endometrial proliferation were significantly reduced by UPA-IUS treatment. The UPA exposed endometria were atrophied with some glandular cysts while the blank controls displayed a proliferative morphology without cysts. Androgen receptors were more intensely stained in the glands of the UPA-IUS treated endometria than in the blank-IUS treated controls.
Conclusions:
In rhesus macaques, a UPA-IUS induced endometrial atrophy and amenorrhea. The work provides proof of principle that an IUS can deliver effective intrauterine concentrations of Ulipristal.
