1 Department of Primate Biology, 2 ChinaUS Primate Biology Laboratory, Kunming Institute of Zoology, Chinese Academy of Sciences, 32 Jiao Chang Dong Lu, Kunming 650223, China and 3 Department of Biological Sciences, University of New Orleans, and Audubon Center for Research of Endangered Species, New Orleans, Louisiana, USA
4 To whom correspondence should be addressed. e-mail: wji{at}mail.kiz.ac.cn
![]() |
Abstract |
---|
![]() ![]() ![]() ![]() ![]() ![]() ![]() |
---|
Key words: embryo development/17-estradiol/oocyte maturation in vitro/progesterone/rhesus monkey
![]() |
Introduction |
---|
![]() ![]() ![]() ![]() ![]() ![]() ![]() |
---|
In vivo, oocyte growth and maturation are directly regulated by intraovarian factors such as steroids, cytokines and other growth factors acting at key points during the process of follicle development (Campbell and McNeilly, 1996; Fulvio, 1996
). Among these factors, estradiol (E2) may be of great importance. In non-primate species such as the rabbit, bovine and hamster, E2 is required for follicular development and maturation in vivo (Richards, 1980
) and also for oocyte fertilization (Suzuki et al., 1984
; Yoshimura et al., 1986
; Saeki et al., 1991
). In contrast to several non-primate species, primates do not require high or increasing E2 levels for follicle growth and oocyte meiotic (nuclear) maturation (Zelinski-Wooten et al., 1993
, 1994
). However, E2 may be important in regulating oocyte cytoplasmic maturation as it is required for acquisition of monkey oocyte fertilization competence (Zelinski-Wooten et al., 1994
). Successful pregnancies were more likely to occur in human IVF using oocytes from follicles that contained higher concentrations of E2 and a higher E2:progesterone ratio (Carson et al., 1982
). However, Morgan et al. (1990
) did not find any correlation between rhesus monkey follicular steroid concentrations and IVF success, while lower E2 levels and higher progesterone:E2 ratios were associated with faster-cleaving embryos. Thus, in primates the absolute level of E2 may be most important for supporting oocyte cytoplasmic maturation. Estradiol was found to act directly at the human oocyte surface during IVM to improve fertilization and cleavage (Tesarik and Mendoza, 1995
). Taken together, these data suggest that E2 may be involved in oocyte embryonic developmental competence, in ways that remain to be clarified. However, this role of E2 is not universal among animals because it inhibited oocyte maturation in frogs (Lin and Schuetz, 1983
).
Progesterone is another intrafollicular steroid mediator of normal mammalian ovarian function. Progesterone is required for ovulation, fertilization, luteinization and maintenance of luteal structure and function in rats and monkeys (Armstrong et al., 1991; Hibbert et al., 1996
). However, with respect to the participation of progesterone in oocyte maturation, little is known in primates or even in rodents, despite limited evidence that levels of progesterone in follicular fluid are closely associated with oocyte maturity and quality. For instance, in humans and rhesus monkeys, high ratios of progesterone to E2 in follicular fluid were correlated with superior embryonic development and pregnancy frequency (Basuray et al., 1988
; Morgan et al., 1990
). In amphibians and fish, it has been known for many years that progesterone or its analogues induces oocyte maturation, acting at the surface of the oocyte rather than by the conventional genomic route (Sadler and Maller, 1982
; Baulieu and Schorderet-Slatkine, 1983
; De Albuja et al., 1983
; Nagahama and Adachi, 1985
; Morrison et al., 2000
).
In our laboratory, we have established chemically defined conditions for IVM of rhesus monkey oocytes that can undergo embryo development following IVF (Zheng et al., 2001a). This serum-free culture system allows examination of hormone actions without complications from undefined serum factors (Bavister, 1995
). Therefore, the present study was designed to test possible roles of E2 and progesterone on the meiotic and developmental competence of rhesus monkey oocytes during IVM as judged by IVF followed by in-vitro culture of embryos.
![]() |
Materials and methods |
---|
![]() ![]() ![]() ![]() ![]() ![]() ![]() |
---|
Oocyte in-vitro maturation
Oocytes were used that appeared normal (round and medium to lightly pigmented), contained an intact nuclear membrane (GV stage) and were enclosed by at least two layers of tightly condensed cumulus cells (cumulusoocyte complexes, COC). The normal COC were randomly grouped and washed four times in their respective culture medium before IVM. In order to sustain the concentrations of steroids in the media drops, 4 ml of mineral oil were incubated with 4 ml of mCMRL-1066 containing no steroid (control) or supplemented with E2 (100 ng/ml, from 50 µg/ml of E2 stock constructed in absolute alcohol) and/or progesterone (3 µg/ml, from 1.5 mg/ml of P4 stock constructed in absolute alcohol) for 3 days. For each of the four IVM culture treatments (control, E2, progesterone, E2 + progesterone; see below), nine 50 µl drops of medium were put into a separate 35 mm plastic Petri dish and covered with 3.5 ml of the corresponding steroid-equilibrated oil and incubated at 37°C for 3 h before addition of oocytes. Five to 10 COC were then placed in several culture drop(s) of each treatment and cultured for 3236 h at 37°C under 5% CO2 in air with 100% humidity. It is likely that COC produce very small amounts of E2 and progesterone during culture with gonadotrophins. To control for any effects of such endogenous steroids, one treatment was included with gonadotrophins but no added steroids. In this study, the purpose was to examine effects of steroid hormones on oocyte developmental competence, and not to directly assess effects on COC function. In five replications of experiment 1 across days, a total of 325 normal-looking COC retrieved from 14 adult rhesus monkey ovaries were matured in: (1) control medium: modified CMRL-1066 (Gibco, NY, USA) (mCMRL-1066) + ovine FSH (5 µg/ml; oFSH-NIADDK-NIH, AFP55518) + ovine LH (10 µg/ml; oLH-NIADDK-NIH, AFP4117); (2) mCMRL-1066 + FSH + LH + E2 (100 ng/ml; Sigma Chemical Co., USA); (3) mCMRL-1066 + FSH + LH + progesterone (3 µg/ml; Sigma); (4) mCMRL-1066 + FSH + LH + E2 + progesterone; and (5) mCMRL-1066 + E2 + progesterone. Medium CMRL was modified by addition of lactate, pyruvate and glutamine (Boatman, 1987
) and contained no macromolecular supplement. A total of 228 normal-looking immature COC were collected from 19 prepubertal female monkeys and used for five replicates across days of experiment 2 in which the COC were cultured in: (1) control medium: mCMRL-1066 + FSH + LH; (2) mCMRL-1066 + FSH + LH + E2; and (3) mCMRL-1066 + FSH + LH + progesterone. Because the availability of ovaries from adult versus prepubertal animals could not be controlled, experiments 1 and 2 were carried out in parallel rather than sequentially.
Oocyte IVF and embryo culture
In all treatments, oocytes that extruded a first polar body (metaphase II, MII) were subjected to the same IVF and embryo culture procedures. Frozenthawed semen was washed then sperm capacitation and IVF were conducted as described previously (Bavister et al., 1983b). Capacitated sperm were co-incubated with the respective treatment groups of MII oocytes for 1216 h at 37°C in a humidified atmosphere of 5% CO2 in air. Adhering sperm and cumulus cells were then removed manually by passing the oocytes through a pulled glass pipette. Oocytes were examined with Nomarski optics for evidence of activation (containing two polar bodies and/or
1 pronucleus). All oocytes containing three or more pronuclei were considered polyspermic and excluded from the fertilization data.
Activated oocytes were washed and cultured in 50 µl drops of mCMRL-1066 (510 per drop) containing 20% bovine calf serum (BCS) at 37°C under oil in a humidified atmosphere of 5% CO2 in air until development was arrested or until hatching (escape from the zona pellucida) occurred. The oocytes were transferred to fresh embryo culture medium every other day. Embryos were examined daily using Nomarski optics (x200400 magnification) on a Nikon Diaphot TMD microscope. Embryos with a pronounced blastocoele cavity were classified as blastocysts.
Measurement of steroid hormone concentrations in culture media under oil
Sets of mCMRL-1066 culture drops under oil like those used for the IVM experiments were prepared containing the same concentrations of E2 or progesterone. An enzyme immunoassay (EIA) as described by Lorenzo et al. (1997) was used to measure concentrations of these steroids remaining in the culture media drops at intervals during incubation for up to 32 h. These measurements were made on three separate occasions. The kit for E2 measurement is ActiveTM Estradiol EIA, DSL-10-4300 (Diagnostic Systems Laboratories, Inc., USA) and the one for progesterone is ActiveTM Progesterone, DSL-10-5000 (Diagnostic Systems Laboratories).
Data analysis
Values for MII were analysed as the percentages of total oocytes, and values for activated oocytes and all stages of embryos were analysed as the percentages of MII oocytes. All percentage data were subjected to arcsin (square root) transformation. The transformed data were analysed by one-way analysis of variance and Fishers protected least significant difference (LSD) test. Values with P < 0.05 were considered statistically significant.
![]() |
Results |
---|
![]() ![]() ![]() ![]() ![]() ![]() ![]() |
---|
|
|
|
|
![]() |
Discussion |
---|
![]() ![]() ![]() ![]() ![]() ![]() ![]() |
---|
The problem of absorption of steroids by the oil overlaying the culture media drops was addressed by equilibrating the oil with the appropriate steroid and by measuring steroid hormone concentrations in the culture medium at intervals during incubation. The concentrations of E2 and of progesterone in the medium reached equilibrium at 8 and
16 h, respectively. Although the concentration of progesterone decreased much more rapidly than that of E2, the final concentrations were about the same, i.e. 3548 ng/ml. These concentrations are similar to that for progesterone (32 ng/ml) but far lower than for E2 (400 ng/ml) in rhesus monkey follicular fluid at the end of 8 days of FSH stimulation (Chaffin et al., 1999
). Nevertheless, the in-vivo concentrations of these hormones are likely to be much greater than those required for their actions on the cumulus/granulosa cells because of the need to maintain adequate systemic steroid hormone levels. Conversely, even though the level of progesterone in the culture drops decreased very rapidly, there was still enough of this steroid to exert a detectable effect on oocyte maturation, as discussed below. By using a high concentration of progesterone at the beginning of incubation (almost 3000 ng/ml), it appears that the capacity of the oil overlay to absorb this steroid was close to being saturated before the oocytes were added, thus sustaining an adequate concentration of between 211 and 48 ng/ml for the duration of oocyte culture. As discussed later, steroid hormones may act very rapidly, through mechanisms including non-genomic pathways, so that the higher concentrations of E2 and progesterone present towards the beginning of oocyte culture (starting 3 h after steroid incubation began, Tables I and II) were sufficient to exert their actions on oocyte maturation, as demonstrated by the data.
For the first time, our data provide evidence that E2 and progesterone significantly improve the developmental competence (cytoplasmic maturation) of primate oocytes during IVM. However, in both experiments 1 and 2, COC matured in all treatments (i.e. with or without steroid hormones present) completed meiotic maturation at similar frequencies, indicating that E2 or progesterone at the levels we used does not alter nuclear maturation of rhesus monkey oocytes. This result is consistent with reports that impairment of steroid biosynthesis in adult monkeys did not affect oocyte meiotic status (Zelinski-Wooten et al., 1994; Hibbert et al., 1996
). Oocyte nuclear maturation was also unaffected after exposure of hamster oocytes to trilostane in vitro (Suzuki et al., 1984
) and of rabbit ovaries to an inhibitor of cholesterol side-chain cleavage enzyme (Yoshimura et al., 1986
). However, data inconsistent with our results were reported by Gould and Graham (1976
) also using prepubertal rhesus monkey females. In that study, progesterone improved the frequency of attaining MII, but cytoplasmic maturation of oocytes was not examined. The discrepancy between these two studies with respect to progesterone could be related to several key experimental differences. In the study by Gould and Graham, oocytes were collected after females had been stimulated with equine chorionic gonadotrophin for 5 days, and cumulus/granulosa cells enclosing oocytes were removed prior to IVM. In addition, Hams F-10 medium + fetal calf serum was used as the IVM culture medium, while progesterone was used at 25 µg/ml versus 3 µg/ml in our study, and the medium concentration may have been much higher due to steroid binding by serum proteins. Yet another difference is that progesterone activity on nuclear maturation was examined in combination with dbcAMP by Gould and Graham (1976
).
It should be also noted that in the present study and other related reports, in-vivo production of E2 and progesterone could not be completely ruled out (Koering et al., 1991; Zelinski-Wooten et al., 1993
, 1994
; Hibbert et al., 1996
), so there could have been some in-vivo priming of COC with endogenous steroids prior to collection. Therefore, we cannot eliminate the possibility that oocyte nuclear maturation in rhesus monkeys requires a very low level of E2 or progesterone.
Several studies have defined the requirement of E2 or progesterone for the acquisition of oocyte fertilizability. For example, experimental reduction of E2 and progesterone production during the follicular phase impaired fertilization of rhesus monkey oocytes (Zelinski-Wooten et al., 1994). Estradiol and/or progesterone also play an important role in supporting normal fertilization in the rat (Zhang and Armstrong, 1989
), hamster (Suzuki et al., 1984
) and rabbit (Yoshimura et al., 1986
). However, our data showed no effect of exogenous E2 or progesterone during IVM on the fertilizability of rhesus monkey oocytes across all treatments in experiments 1 and 2. Similarly, Morgan et al. (1990
) and Basuray et al. (1988
) found no relationship between the follicular fluid steroid (E2 and progesterone) content and oocyte fertilization in rhesus monkey and human. It is possible that low endogenous levels of E2 and progesterone in the monkeys used in this study are adequate to support cytoplasmic events in oocytes that are required for the occurrence of fertilization. If so, we would not expect to find an additional effect of steroids in the IVM culture medium on fertilization.
Consistent with the present study, few (4%) or no blastocysts were produced from IVM oocytes obtained during the non-breeding season from adult rhesus monkeys, whether the animals were FSH-stimulated or not; and IVM oocytes from unstimulated animals during the breeding season also did not develop into blastocysts (Zheng et al., 2001b). The poor development of some IVM oocytes past the 8-cell stage in some conditions may be related to improper activation of the embryonic genome due to defective maturation (Schramm et al., 2003
). Only when monkeys were stimulated with FSH during the breeding season (Zheng et al., 2001a
,b) did their IVM oocytes produce blastocysts at a level (1630%) similar to that obtained in the present study. In both of these studies (Zheng et al., 2001a
,b), no E2 or progesterone was used in the IVM culture medium. The blastocyst development results obtained in these studies and in the present work could be reconciled by a need during oocyte maturation for steroid hormones that are either produced in vivo under the influence of FSH (to which monkeys respond readily only in the breeding season) or supplied in vitro during oocyte culture, as in the present study. Inclusion of steroid hormones in the culture medium for IVM supports cytoplasmic maturation and allows use of oocytes from unstimulated rhesus monkeys for research throughout the year, which is advantageous in view of the prolonged period (summer months) during which these animals are refractory to FSH stimulation for augmenting oocyte collection in vivo.
In experiment 1, oocytes matured in the media containing E2 or progesterone or both steroids, with or without gonadotrophin supplementation (treatments 25), exhibited similar development to morulae and/or blastocysts. These responses were all significantly greater than the response in control medium with gonadotrophins but without added steroids (treatment 1, 0% blastocysts). No blastocysts were produced without the presence of one or other or both of these steroid hormones during IVM. Therefore, any effect of gonadotrophins on cumulus cells is not sufficient, and addition of steroid hormones to the culture medium is necessary to support full developmental competence of IVM oocytes. Moreover, it appears that the gonadotrophins do not augment the effects of steroid hormones on cytoplasmic maturation during IVM, because gonadotrophins did not produce any significant improvement when combined with E2 and progesterone compared with the responses obtained with steroid hormones alone. Thus, unlike the situation in vivo (Armstrong et al., 1991; McDonnell and Goldman, 1994
; Graham et al., 1995
), we did not detect any synergistic effect between the actions of E2, progesterone and gonadotrophins under in-vitro conditions. The stimulation of oocyte developmental competence in vitro by E2 and progesterone is consistent with observations in rhesus monkey and human showing a positive correlation between (i) the follicular fluid content of E2 or the progesterone to E2 ratio and (ii) embryo developmental potential and establishment of pregnancy (Botero-Ruiz et al., 1984
; Reinthaller et al., 1987
; Basuray et al., 1988
; Morgan et al., 1990
). Furthermore, E2 has been reported to act on human oocytes during IVM to enhance their fertilization and cleavage competence (Tesarik and Mendoza, 1995
). However, the classic nuclear estrogen receptor (ER) is not expressed in rhesus monkey granulosa cells (Hild-petito et al., 1988
; Chandrasekher et al., 1994
), and the progesterone receptor (PR) is absent from granulosa cells until after the mid-cycle LH surge (Chandrasekher et al., 1994
). Therefore, we propose that the actions of E2 and progesterone on primate oocyte developmental competence might be mediated rapidly through the non-genomic mechanism via cell membrane receptors, as shown for meiotic control in studies with Xenopus (Wasserman et al., 1980
; Sadler and Maller, 1982
; Liu and Patino, 1993
; Bayaa et al., 2000
). In Xenopus, progesterone operates through a plasma membrane-associated tyrosine kinase to activate phospholipase C (Morrison et al., 2000
). It will be interesting to determine whether progesterone exerts its action on cytoplasmic maturation in mammalian oocytes via a similar mechanism.
Cell membrane ER, which transfer the signal cascade through Ca2+ release after binding with E2, have been detected in pig and chicken granulosa cells (Morley et al., 1992), and were also reported in human oocytes to mediate the stimulatory action of E2 on oocyte fertilization and cleavage potentials (Tesarik and Mendoza, 1995
). This is consistent with the elevation of intracellular calcium and activation of plasma membrane tyrosine kinase by progesterone during IVM in amphibians (Wasserman et al., 1980
; Morrison et al., 2000
). In trilostane-treated rhesus monkeys, replacement therapy with the progestin agonist R5020 was able to restore ovulation but failed to restore the oocytes fertilizability and therefore indicates the alternative mechanism of progesterone action directly on cell membranes (Hibbert et al., 1996
). However, in rhesus monkey follicles, no cell membrane ER or PR has been reported to date. Therefore, further studies are needed to clarify the mechanism of E2 and progesterone actions on primate oocyte maturation in vitro.
As in the adult monkeys, maturation of COC from prepubertal females in medium supplemented with E2 or progesterone also supported significantly higher frequencies of morula development (Table IV, treatments 2 and 3) when compared with the control (treatment 1). These results confirm the conclusion from experiment 1 that E2 and progesterone can improve oocyte developmental competence (cytoplasmic maturation). However, there was a difference between the COC from adult and prepubertal animals. The COC from prepubertal females had poorer developmental response to steroids than their counterparts from adult ovaries as assessed by the embryos progression to blastocysts. The presence of E2 or progesterone in media for oocyte IVM failed to stimulate blastocyst formation in prepubertal monkeys (Table IV), whereas 1420% blastocysts were obtained from oocytes of adults after IVM with steroids (Table III). Similarly, in cattle, the marked positive effect of serum on cow oocyte maturation was not observed with calf oocytes (Lonergan et al., 1994; Khatir et al., 1996
). Comparing the developmental responses between E2/progesterone-supported IVM oocytes from adult versus prepubertal monkeys (Tables III and IV), it is evident that while 3144% of morulae progressed into blastocysts in experiment 1, only 07% did so in experiment 2. This discrepancy illustrates the importance of the morula-to-blastocyst transformation for revealing defects in oocytes or embryos, as well as reinforcing the difference in competence of the IVM oocytes from the young versus adult animals. It has been suggested that mammalian oocytes obtain their developmental competence in a progressive or stepwise manner during maturation, and that this process may be distorted by IVM (Eppig et al., 1994
; Eppig, 1996
; Schramm and Bavister, 1999
). The ability to progress to the blastocyst stage may be acquired relatively late in oocyte growth and maturation (Eppig and Schroeder, 1989
; Eppig et al., 1994
; Schramm and Bavister, 1999
). The absence of E2 and progesterone actions on blastocyst formation in experiment 2 possibly reflects that the mechanism responsible for blastocyst formation is not established in COC before puberty. However, in-vivo priming with FSH markedly improved the competence of prepubertal monkey oocytes to progress to the blastocyst stage (Zheng et al., 2001b
). Thus, we propose that in rhesus monkeys, the in-vivo action of FSH is important for COC to respond to steroids by developing the capability to form blastocysts.
In summary, the present study demonstrates that E2 and progesterone stimulate rhesus monkey oocyte developmental capacity during IVM, and suggests an in-vivo role of these steroid hormones in local modulation of oocyte cytoplasmic maturation in primates. It shows that gonadotrophins in the absence or in the presence of steroid hormones are not effective in stimulating either nuclear or cytoplasmic maturation in vitro of monkey oocytes. Additionally, we have validated the use of a chemically defined culture system for oocytes from unstimulated rhesus monkeys that allows examination of the contribution of specific agents to IVM. This culture system can support frequencies of blastocyst formation similar to those obtained with oocytes from FSH-primed adult rhesus monkeys matured in vitro using undefined, serum-containing culture media (Zheng et al., 2001b). However, this system still does not support rhesus oocyte developmental competence at the levels observed with oocytes matured in vivo (Schramm and Bavister, 1999
). We anticipate that defined culture systems like this will assist basic research into cytoplasmic maturation and perhaps can be applied to the clinical treatment of human infertility using immature oocytes collected from natural cycles.
![]() |
Acknowledgements |
---|
![]() |
References |
---|
![]() ![]() ![]() ![]() ![]() ![]() ![]() |
---|
Armstrong, D.T., Zhang, X., Vanderhyden, B.C. and Khamsi, F. (1991) Hormonal actions during oocyte maturation influence fertilization and early embryonic development. Ann. NY Acad. Sci., 626, 137158.[Abstract]
Barnes, F.L., Kausche, A., Tiglias, J., Wood, C., Wilton, L. and Trounson, A. (1996) Production of embryos from in vitro-matured primary human oocytes. Fertil. Steril., 65, 11511156.[ISI][Medline]
Basuray, R., Rawlins, R.G., Radwanska, E., Henig, I., Sachdeva, S., Tummon, I., Binor, Z., and Dmowski, W.P. (1988) High progesterone/estradiol ratio in follicular fluid at oocyte aspiration for in vitro fertilization as a predictor of possible pregnancy. Fertil. Steril., 49, 10071011.[ISI][Medline]
Baulieu, E.E. and Schorderet-Slatkine, S. (1983) Steroidal and peptidic control mechanisms in membrane of Xenopus laevis oocytes resuming meiotic division. J. Steroid Biochem., 19, 139145.[ISI][Medline]
Bavister, B.D. (1995) Culture of preimplantation embryos: facts and artifacts. Hum. Reprod. Update, 1, 91148.[ISI]
Bavister, B.D., Leibfried, M.L. and Lieberman, G. (1983a) Development of preimplantation embryos of the golden hamster in a defined culture medium. Biol. Reprod., 28, 235247.[Abstract]
Bavister, B.D., Boatman, D.E., Leibfried, M.L., Loose, M. and Vernon, M.W. (1983b) Fertilization and cleavage of rhesus monkey oocytes in vitro. Biol. Reprod., 28, 983999.[ISI][Medline]
Bayaa, M., Booth, R.A., Sheng, Y. and Liu, X.J. (2000) The classical progesterone receptor mediates xenopus oocyte maturation through a nongenomic mechanism. Proc. Natl Acad. Sci. USA, 97, 1260712612.
Boatman, D.E. (1987) In vitro growth of non-human primate pre- and peri-implantation embryos. In Bavister, B.D. (ed.), The Mammalian Preimplantation Embryo. Regulation of Growth and Differentiation. Plenum Press, New York, pp. 273308.
Botero-Ruiz, W., Laufer, N., DeCherney, A.H., Polan, M.L., Haseltine, F.P. and Behrman, H.R. (1984) The relationship between follicular fluid steroid concentration and successful fertilization of human oocytes in vitro. Fertil. Steril., 41, 820826.[ISI][Medline]
Campbell, B.K. and McNeilly, A.S. (1996) Follicular dominance and oocyte maturation. Zygote, 4, 327334.[ISI][Medline]
Carson, R.S., Trounson, A.O. and Findlay, J.K. (1982) Successful fertilisation of human oocytes in vitro: concentration of estradiol-17, progesterone and androstenedione in the antral fluid of donor follicles. J. Clin. Endocrinol. Metab., 55, 798800.[Abstract]
Cha, K.Y. and Chian, R.C. (1998) Maturation in vitro of immature human oocytes for clinical use. Hum. Reprod. Update, 4, 103120.
Cha, K.Y., Han, S.Y., Chung, H.M., Choi, D.H., Lim, J.M., Lee, W.S., Ko, J.J. and Yoon, T.K. (2000) Pregnancies and deliveries after in vitro maturation culture followed by in vitro fertilization and embryo transfer without stimulation in women with polycystic ovary syndrome. Fertil. Steril., 73, 978983.[CrossRef][ISI][Medline]
Chaffin, C.L., Hess, D.L. and Stouffer, R.L. (1999) Dynamics of periovulatory steroidogenesis in the rhesus monkey follicle after ovarian stimulation. Hum. Reprod., 14, 642649.
Chandrasekher, Y.A., Melner, M.H., Nagalla, S.R. and Stouffer, R.L. (1994) Progesterone receptor, but not estradiol receptor, messenger ribonucleic acid is expressed in luteinizing granulosa cells and the corpus luteum in rhesus monkeys. Endocrinology, 135, 307314.[Abstract]
De Albuja, C.M., Campos, M. and Del Pino, E.M. (1983) Role of progesterone on oocyte maturation in the egg-brooding hylid frog Gastrotheca riobambae (Fowler). J. Exp. Zool., 227, 271276.[ISI][Medline]
Eppig, J.J. (1996) Coordination of nuclear and cytoplasmic oocyte maturation in eutherian mammals. Reprod. Fertil. Dev., 8, 485489.[ISI][Medline]
Eppig, J.J. and Schroeder, A.C. (1989) Capacity of mouse oocytes from preantral follicles to undergo embryogenesis and development to live young after growth, maturation, and fertilization in vitro. Biol. Reprod., 41, 268276.[Abstract]
Eppig, J.J., Schultz, R.M., OBrien, M. and Chesnel, F. (1994) Relationship between the developmental programs controlling nuclear and cytoplasmic maturation of mouse oocytes. Dev. Biol., 164, 19.[CrossRef][ISI][Medline]
Fulvio, C. (1996) Intra-ovarian regulation of oocyte developmental competence in cattle. Zygote, 4, 323326.[ISI][Medline]
Galli, C. and Moor, R.M. (1991) Gonadotrophin requirements for the in vitro maturation of sheep oocytes and their subsequent embryonic development. Theriogenology, 35, 10831093.[ISI]
Gilchrist, R.B., Nayudu, P.L. and Hodges, J.K. (1997) Maturation, fertilization, and development of marmoset monkey oocytes in vitro. Biol. Reprod., 56, 238246.[Abstract]
Goldenberg, R.L., Vaitukaitis, J.L. and Ross, G.T. (1972) Estrogen and follicle-stimulating hormone interactions on follicle growth in rats. Endocrinology, 90, 14921498. [ISI][Medline]
Gould, K.G. and Graham, C.E. (1976) Maturation in vitro of oocytes recovered from prepubertal rhesus monkeys. J. Reprod. Fertil., 46, 269270.[CrossRef][Medline]
Graham, J.D., Roman, S.D., McGowan, E., Sutherland, R.L. and Clarke, C.L. (1995) Preferential stimulation of human progesterone receptor B expression by estrogen in T-47D human breast cancer cells. J. Biol. Chem., 270, 3069330700.
Hibbert, M., Stouffer, R.L., Wolf, D.P. and Zelinski-Wooten, M.B. (1996) Midcycle administration of a progesterone synthesis inhibitor prevents ovulation in primates. Proc. Natl Acad. Sci. USA, 93, 18971901.
Hild-petito, S., Stouffer, R.L. and Brenner, R.M. (1988) Immunocytochemical localization of estradiol and progesterone receptors in the monkey ovary through the menstrual cycle. Endocrinology, 123, 28962905.[Abstract]
Khatir, H., Lonergan, P., Carolan, C. and Mermillod, P. (1996) Prepubertal bovine oocyte: a negative model for studying oocyte developmental competence. Mol. Reprod. Dev., 45, 231239.[CrossRef][ISI][Medline]
Koering, M.J., Danforth, D.R. and Hodgen, G.D. (1991) Early folliculogenesis in primate ovaries: testing the role of estrogen. Biol. Reprod., 45, 890897.[Abstract]
Krisher, R.L. and Bavister, B.D. (1998) Responses of oocytes and embryos to the culture environment. Theriogenology, 49, 103114.[CrossRef][ISI][Medline]
Lin, Y.W. and Schuetz, A.W. (1983) In vitro estrogen modulation of pituitary and progesterone-induced oocyte maturation in Rana pipiens. J. Exp. Zool., 226, 281291.[ISI][Medline]
Liu, Z. and Patino, R. (1993) High-affinity binding of progesterone to the plasma membrane of Xenopus oocytes: characteristics of binding and hormonal and developmental control. Biol. Reprod., 49, 980988.[Abstract]
Lonergan, P., Carolan, C. and Mermillod, P. (1994) Development of bovine embryos in vitro following oocyte maturation under defined conditions. Reprod. Nutr. Dev., 34, 329339.[ISI][Medline]
Lorenzo, P.L., Illera, J.C., Silvan, G., Munro, C.J., Rebollar, P.G., Alvarino, J.M., Illera, M.J. and Illera, M. (1997) A sensitive EIA for 17-estradiol and progesterone in culture medium for oocyte in vitro maturation procedures. Rev. Esp. Fisiol., 53, 271280.[Medline]
McDonnell, D.P. and Goldman, M.E. (1994) RU486 exerts antiestrogenic activities through a novel progesterone receptor A form-mechanism. J. Biol. Chem., 269, 1194511949.
Morgan, P.M., Boatman, D.E. and Bavister, B.D. (1990) Relationships between follicular fluid steroid hormone concentrations, oocyte maturity, in vitro fertilization and embryonic development in the rhesus monkey. Mol. Reprod. Fertil., 27, 145151.
Morgan, P.M., Warikoo, P.K. and Bavister, B.D. (1991) In vitro maturation of ovarian oocytes from unstimulated rhesus monkeys: assessment of cytoplasmic maturity by embryonic development after in vitro fertilization. Biol. Reprod., 45, 8993.[Abstract]
Morley, P., Whitfield, J.F., Vanderhyden, B.C., Tsang, B.K. and Schwartz, J.L. (1992) A new, nongenomic estrogen action: the rapid release of intracellular calcium. Endocrinology, 131, 13051312.[Abstract]
Morrison, T., Waggoner, L., Whitworth-Langley, L. and Stith, B.J. (2000) Nongenomic action of progesterone: activation of Xenopus oocyte phospholipase C through a plasma membrane-associated tyrosine kinase. Endocrinology, 141, 21452152.
Nagahama, Y. and Adachi, S. (1985) Identification of maturation-inducing steroid in a teleost, the amago salmon (Oncorhynchus rhodurus). Dev. Biol., 109, 428435.[ISI][Medline]
Paulson, R.J., Sauer, M.V., Francis, M.M., Macaso, T.M. and Lobo, R.A. (1994) Factors affecting pregnancy success of human in-vitro fertilization in unstimulated cycles. Hum. Reprod., 9, 15711575.[Abstract]
Reinthaller, A., Deutinger, J., Riss, P., Muller-Tyl, E., Fischl, F., Bieglmayer, C. and Janisch, H. (1987) Relationship between the steroid and prolactin concentration in follicular fluid and the maturation and fertilization of human oocytes. J. In Vitro Fertil. Embryo Transfer, 4, 228231.[ISI][Medline]
Richards, J. (1980) Maturation of ovarian follicles: actions and interactions of pituitary and ovarian hormones on follicular cell differentiation. Physiol. Rev., 60, 5189.
Rose-Hellekant, T.A., Libersky-Williamson, E.A. and Bavister, B.D. (1998) Energy substrates and amino acids provided during in vitro maturation of bovine oocytes alter acquisition of developmental competence. Zygote, 6, 285294.[CrossRef][ISI][Medline]
Sadler, S.E. and Maller, J.L. (1982) Identification of a steroid receptor on the surface of Xenopus oocytes by photoaffinity labeling. J. Biol. Chem., 257, 355361.
Saeki, K., Hoshi, M., Leibfried-Rutledge, M.L. and First, N.L. (1991) In vitro fertilization and development of bovine oocytes matured in serum-free medium. Biol. Reprod., 44, 256260.[Abstract]
Schramm, R.D. and Bavister, B.D. (1996) Granulosa cells from follicle-stimulating hormone-primed monkeys enhance the developmental competence of in vitro matured oocytes from non-stimulated rhesus monkeys. Hum. Reprod., 11, 16981702.[Abstract]
Schramm, R.D. and Bavister, B.D. (1999) A macaque model for studying mechanisms controlling oocyte development and maturation in primates. Hum. Reprod., 14, 25442555.
Schramm, R.D. and Paprocki, A.M. (2000) Birth of rhesus monkey infant after transfer of embryos derived from in-vitro matured oocytes: short communication. Hum. Reprod., 15, 24112414.
Schramm, R.D., Tennier, M.T., Boatman, D.E. and Bavister, B.D. (1993) Chromatin configurations and meiotic competence of oocytes are related to follicular diameter in nonstimulated rhesus monkeys. Biol. Reprod., 48, 349356.[Abstract]
Schramm, R.D., Paprocki, A.M. and VandeVoort, C.A. (2003) Causes of developmental failure of in-vitro matured rhesus monkey oocytes: impairments in embryonic genome activation. Hum. Reprod., 18, 826833.
Schroeder, A.C. and Eppig, J.J. (1984) The developmental capacity of mouse oocytes that matured spontaneously in vitro is normal. Dev. Biol., 102, 493497.[ISI][Medline]
Sirard, M.A., Parrish, J.J., Ware, C.B., Leibfried-Rutledge, M.L. and First, N.L. (1988) The culture of bovine oocytes to obtain developmentally competent embryos. Biol. Reprod., 39, 546552.[Abstract]
Spindler, R.E., Pukazhenthi, B.S. and Wildt, D.E. (2000) Oocyte metabolism predicts the development of cat embryos to blastocyst in vitro. Mol. Reprod. Dev., 56, 163171.[CrossRef][ISI][Medline]
Suikkari, A.M., Tulppala, M., Tuuri, T., Hovatta, O. and Barnes, F. (2000) Luteal phase start of low-dose FSH priming of follicles results in an efficient recovery, maturation and fertilization of immature human oocytes. Hum. Reprod., 15, 747751.
Suzuki, S., Endo, Y., Miura, R. and Iizuka, R. (1984) Biological effects of trilostane in vitro on oocyte maturation and fertilization in the hamster. Experientia, 40, 12141217.[ISI][Medline]
Tesarik, J. and Mendoza, C. (1995) Nongenomic effects of 17-estradiol on maturing human oocytes: relationship to oocyte developmental potential. J. Clin. Endocrinol. Metab., 80, 14381443.[Abstract]
Trounson, A., Wood, C. and Kausche, A. (1994) In vitro maturation and the fertilization and developmental competence of oocytes recovered from untreated polycystic ovarian patients. Fertil. Steril., 62, 353362.[ISI][Medline]
Walker, M.L., Wilson, M.E. and Gordon, T.P. (1984) Endocrine control of the seasonal occurrence of ovulation in rhesus monkeys housed outdoors. Endocrinology, 114, 10741081.[Abstract]
Wasserman, W.J., Pinto, L.H., OConnor, C.M. and Smith, L.D. (1980) Progesterone induces a rapid increase in [Ca2+]i of Xenopus laevis oocytes. Proc. Natl Acad. Sci. USA, 77, 15341536.[Abstract]
Yoshimura, Y., Hosoi, Y., Atlas, S.J., Bongiovanni, A.M., Santulli, R. and Wallach, E.E. (1986) The effect of ovarian steroidogenesis on ovulation and fertilizability in the in vitro perfused rabbit ovary. Biol. Reprod., 35, 943948.[Abstract]
Zelinski-Wooten, M.B., Hess, D.L., Baughman, W.L., Molskness, T.A., Wolf, D.P. and Stouffer, R.L. (1993) Administration of an aromatase inhibitor during the late follicular phase of gonadotrophin-treated cycles in rhesus monkeys: effects on follicle development, oocyte maturation, and subsequent luteal function. J. Clin. Endocrinol. Metab., 76, 988995.[Abstract]
Zelinski-Wooten, M.B., Hess, D.L., Wolf, D.P. and Stouffer, R.L. (1994) Steroid reduction during ovarian stimulation impairs oocyte fertilization, but not folliculogenesis, in rhesus monkeys. Fertil. Steril., 61, 11471155.[ISI][Medline]
Zhang, X. and Armstrong, D.T. (1989) Effects of follicle-stimulating hormone and ovarian steroids during in vitro meiotic maturation on fertilization of rat oocytes. Gamete Res., 23, 267277.[ISI][Medline]
Zheng, P., Wang, H., Bavister, B.D. and Ji, W. (2001a) Maturation of rhesus monkey oocytes in chemically defined culture media and their functional assessment by IVF and embryo development. Hum. Reprod., 16, 300305.
Zheng, P., Si, W., Wang, H., Zou, R., Bavister, B.D. and Ji, W. (2001b) Effect of age and breeding season on the developmental capacity of oocytes from unstimulated and FSH-stimulated rhesus monkeys. Biol. Reprod., 64, 14171421.
Submitted on April 17, 2001; resubmitted on May 22, 2003; accepted on June 26, 2003.