Jessica E. Stanley

Evaluation of antral follicle growth in the macaque ovary during the menstrual cycle and controlled ovarian stimulation by high-resolution ultrasonography

To date, ultrasonography of monkey ovaries is rare and typically of low resolution. The objectives of this study were to use state‐of‐the‐art, high‐resolution, transabdominal ultrasonography with real‐time Doppler capabilities to: (1) determine whether one can reliably detect in real time the large dominant follicle, the corpus luteum (CL), and small (<2 mm) antral follicles on the ovaries of rhesus monkeys during the natural menstrual cycle; and (2) predict the follicular response of rhesus ovaries to controlled ovarian stimulation (COS) protocols. Rhesus monkeys were selected for transabdominal ultrasonography using a GE Voluson 730 Expert Doppler System at discrete stages of the menstrual cycle. Subsequently, serial ultrasound scanning was employed to observe growth of antral follicles and the CL. Finally, females were scanned to assess follicular growth during COS. The dominant structure and small antral follicles (<2 mm) were reliably visualized in real time. The follicle destined to ovulate could be identified by size differential by day 3 of the follicular phase. The number of small antral follicles present before onset of COS protocol correlated positively with the number of metaphase II‐stage oocytes collected after treatment. The results of this study demonstrate that the population dynamics of antral follicle pools can be noninvasively evaluated in monkeys during natural and pharmacologic ovarian cycles. Am. J. Primatol. 71:384–392, 2009.

The phosphodiesterase 3 inhibitor ORG 9935 inhibits oocyte maturation in the naturally selected dominant follicle in rhesus macaques

BACKGROUND The study was conducted to determine whether the phosphodiesterase (PDE) 3 inhibitor ORG 9935 prevents the resumption of meiosis in primate oocytes during natural menstrual cycles. STUDY DESIGN Regularly cycling adult female macaques (n=8) were followed during the follicular phase and then started on a 2-day treatment regimen of human recombinant gonadotropins to control the timing of ovulation. Monkeys received no further treatment (controls) or ORG 9935. Oocytes were recovered by laparoscopic follicle aspiration 27 h after an ovulatory stimulus, cultured in vitro in the absence of inhibitor and inseminated. The primary outcome was the meiotic stage of the oocyte. RESULTS In six ORG 9935 cycles, five of the recovered oocytes were germinal vesicle (GV)-intact, and one exhibited GV breakdown (GVBD). In contrast, all three oocytes that recovered during control cycles were GVBD (p<.05). None of the ORG 9935-treated oocytes underwent fertilization compared with 2/3 (67%) from controls. CONCLUSIONS These results demonstrate that ORG 9935 blocks resumption of meiosis in the naturally selected dominant follicle in primates and suggest that PDE3 inhibitors have potential clinical use as contraceptives in women.

Evaluation of the phosphodiesterase 3 inhibitor ORG 9935 as a contraceptive in female macaques: Initial trials

BACKGROUND The study was conducted to determine whether a phosphodiesterase (PDE) 3 inhibitor has potential as a novel contraceptive in primates. METHODS Regularly cycling adult female cynomolgus macaques of proven fertility (n=16) were treated for 7 months with placebo (controls) or the PDE3 inhibitor ORG 9935 as a daily food treat (150 mg/kg) or as a weekly depot injection (150 mg/kg, sc). After 1 month, a male of proven fertility was introduced into each group. Females underwent weekly monitoring of progesterone (P) and ultrasound evaluation for pregnancy if P remained elevated (1.0 ng/mL) >3 weeks. ORG 9935 values were evaluated using high-performance liquid chromatography. RESULTS Overall, the pregnancy rate in ORG 9935-treated monkeys (4/8, 50%) did not differ from controls (7/8, 88%; p=.5). However, no animal became pregnant in a cycle when the serum level of ORG 9935 exceeded 300 nmol/L. Moreover, two treated monkeys who mated throughout the treatment phase and did not conceive became pregnant within four cycles after stopping ORG 9935. The other two animals were discontinued prematurely from the protocol. CONCLUSIONS These results demonstrate that ORG 9935 may prevent pregnancy in primates at serum concentrations above 300 nmol/L and that the effect is reversible.