scholarly journals Inactivation of glucocorticoids by 11β-hydroxysteroid dehydrogenase enzymes increases during the meiotic maturation of porcine oocytes

Reproduction ◽  
2008 ◽  
Vol 136 (6) ◽  
pp. 725-732 ◽  
Author(s):  
Rachel J Webb ◽  
Neera Sunak ◽  
Lisa Wren ◽  
Anthony E Michael
Keyword(s):  
Oocyte Maturation ◽  
Enzyme Activities ◽  
Germinal Vesicle ◽  
Hydroxysteroid Dehydrogenase ◽  
Target Cells ◽  
Cortisol Metabolism ◽  
Enzymatic Inactivation ◽  
Glucocorticoid Metabolism ◽  
Ovarian Cyst Fluid

Recent reports have shown that glucocorticoids can modulate oocyte maturation in both teleost fish and mammals. Within potential target cells, the actions of physiological glucocorticoids are modulated by 11β-hydroxysteroid dehydrogenase (HSD11B) isoenzymes that catalyse the interconversion of cortisol and cortisone. Hence, the objective of this study was to establish whether HSD11B enzymes mediate cortisol–cortisone metabolism in porcine oocytes and, if so, whether the rate of glucocorticoid metabolism changes during oocyte maturation. Enzyme activities were measured in cumulus–oocyte complexes (COCs) and denuded oocytes (DOs) using radiometric conversion assays. While COCs and DOs oxidised cortisol to inert cortisone, there was no detectable regeneration of cortisol from cortisone. The rate of cortisol oxidation was higher in expanded COCs than in compact COCs containing germinal vesicle (GV) stage oocytes (111±6 vs 2041±115 fmol cortisone/oocyte.24 h; P<0.001). Likewise, HSD11B activities were 17±1 fold higher in DOs from expanded COCs than in those from compact COCs (P<0.001). When GV stage oocytes were subject to a 48 h in vitro maturation protocol, the enzyme activities were significantly increased from 146±18 to 1857±276 fmol cortisone/oocyte.24 h in GV versus MII stage oocytes respectively (P<0.001). Cortisol metabolism was inhibited by established pharmacological inhibitors of HSD11B (glycyrrhetinic acid and carbenoxolone), and by porcine follicular and ovarian cyst fluid. We conclude that an HSD11B enzyme (or enzymes) functions within porcine oocytes to oxidise cortisol, and that this enzymatic inactivation of cortisol increases during oocyte maturation.

scholarly journals Glucocorticoid metabolism and reproduction: a tale of two enzymes

Reproduction ◽  
2003 ◽  
pp. 425-441 ◽  
Author(s):  
AE Michael ◽  
LM Thurston ◽  
MT Rae
Keyword(s):  
Target Cells ◽  
Cellular Mechanisms ◽  
Cortisol Metabolism ◽  
Wide Range ◽  
Uterine Growth ◽  
Enzymatic Inactivation ◽  
Intra Uterine Growth Retardation ◽  
Endogenous Modulators ◽  
Glucocorticoid Metabolism ◽  
Reproductive Processes

Within potential target cells, the actions of physiological glucocorticoids (cortisol and corticosterone) are modulated by isoforms of the enzyme 11 beta-hydroxysteroid dehydrogenase (11 beta HSD). To date, two isoforms of 11 beta HSD have been cloned: 11 beta HSD1 acts predominantly as an NADP(H)-dependent reductase to generate active cortisol or corticosterone, and 11 beta HSD2 is a high affinity NAD(+)-dependent enzyme that catalyses the enzymatic inactivation of glucocorticoids. Whereas the regeneration of active glucocorticoids by 11 beta HSD1 has been implicated in the cellular mechanisms of pituitary function, ovulation and parturition, the enzymatic inactivation of cortisol and corticosterone by 11 beta HSD enzymes appears to be central to the protection of gonadal steroidogenesis, prevention of intra-uterine growth retardation, and lactation. Recent evidence indicates that follicular fluid contains endogenous modulators of cortisol metabolism by 11 beta HSD1, the concentrations of which are associated with the clinical outcome of assisted conception cycles and are altered in cystic ovarian disease. In conclusion, the two cloned isoforms of 11 beta HSD fulfil diverse roles in a wide range of reproductive processes from conception to lactation.

scholarly journals Requirement of mosXe protein kinase for meiotic maturation of Xenopus oocytes induced by a cdc2 mutant lacking regulatory phosphorylation sites.

1992 ◽  
Vol 12 (7) ◽  
pp. 3192-3203 ◽  
Author(s):  
K M Pickham ◽  
A N Meyer ◽  
J Li ◽  
D J Donoghue
Keyword(s):  
Protein Kinase ◽  
Oocyte Maturation ◽  
Xenopus Oocytes ◽  
Germinal Vesicle ◽  
Cyclin B1 ◽  
Phosphorylation Sites ◽  
Germinal Vesicle Breakdown ◽  
Regulatory Phosphorylation

The p34cdc2 protein kinase is a component of maturation-promoting factor, the master regulator of the cell cycle in all eukaryotes. The activity of p34cdc2 is itself tightly regulated by phosphorylation and dephosphorylation. Predicted regulatory phosphorylation sites of Xenopus p34cdc2 were mutated in vitro, and in vitro-transcribed RNAs were injected into Xenopus oocytes. The cdc2 single mutants Thr-14----Ala and Tyr-15----Phe did not induce germinal vesicle breakdown (BVBD) upon microinjection into oocytes. In contrast, the cdc2 double mutant Ala-14/Phe-15 did induce GVBD. Both the Ala-14 and Ala-14/Phe-15p34cdc2 mutants were shown to coimmunoprecipitate cyclin B1 and to phosphorylate histone H1 in immune complex kinase assays. Microinjection of antisense oligonucleotides to c-mosXe was used to demonstrate the role of mos protein synthesis in the induction of GVBD by the Ala-14/Phe-15 cdc2 mutant. Thr-161 was also mutated. p34cdc2 single mutants Ala-161 and Glu-161 and triple mutants Ala-14/Phe-15/Ala-161 and Ala-14/Phe-15/Glu-161 failed to induce GVBD in oocytes and showed a decreased binding to cyclin B1 in coimmunoprecipitations. Each of the cdc2 mutants was also assayed by coinjection with cyclin B1 or c-mosXe RNA into oocytes. Several of the cdc2 mutants were found to affect the kinetics of cyclin B1 and/or mos-induced GVBD upon coinjection, although none affected the rate of progesterone-induced maturation. We demonstrate here the significance of Thr-14, Tyr-15, and Thr-161 of p34cdc2 in Xenopus oocyte maturation. In addition, these results suggest a regulatory role for mosXe in induction of oocyte maturation by the cdc2 mutant Ala-14/Phe-15.

scholarly journals Effects of gonadotrophin in vivo and 2-hydroxyoestradiol-17β in vitro on follicular steroid hormone profile associated with oocyte maturation in the catfish Heteropneustes fossilis

2006 ◽  
Vol 189 (2) ◽  
pp. 341-353 ◽  
Author(s):  
A Mishra ◽  
K P Joy
Keyword(s):  
Oocyte Maturation ◽  
Germinal Vesicle ◽  
Hplc Method ◽  
Heteropneustes Fossilis ◽  
Germinal Vesicle Breakdown ◽  
Steroid Profile ◽  
17 Hydroxyprogesterone ◽  
Envelope Layer

An HPLC method was used to tentatively identify progesterone (P4) and its metabolites (17-hydroxyprogesterone (17-P4) and 17,20β-dihydroxy-4-pregnen-3-one (17,20β-P)), corticosteroids (cortisol and corticosterone) and testosterone in ovary/follicular preparations of the catfish Heteropneustes fossilis associated with in vivo or in vitro oocyte maturation/ovulation. A single i.p. injection of human chorionic gonadotrophin (100 IU/fish, sampled at 0, 8 and 16 h) induced oocyte maturation and ovulation, which coincided with significant and progressive increases in 17,20β-P, and P4 and 17-P4, the precursors of the former. Both cortisol and corticosterone also increased significantly. Conversely, testosterone decreased significantly and progressively over time. Under in vitro conditions, incubation of post-vitellogenic (intact) follicles or follicular envelope (layer) with 2-hydroxyoestradiol (2-OHE2, 5 μM for 0, 6 and 24 h) elicited a sharp significant increase in 17,20β-P, the increase being higher in the follicular envelope incubate. P4 and 17-P4 also registered significant increases over the time with the peak values at 24 h. Cortisol and corticosterone increased significantly in the intact follicle, but not in the follicular envelope incubate. Testosterone decreased significantly in the intact follicle, but increased significantly (24 h) in the follicular envelope incubate. Coincident with these changes, the percentage of germinal vesicle breakdown (GVBD) increased over the time in the intact follicle incubate (48.9% at 6 h and 79.8% at 24 h). Denuded oocytes on incubation with 2-OHE2 (5 μM) did not produce any significant change in the percentage of GVBD or in the steroid profile. While corticosterone and 17,20β-P were undetected, P4, 17-P4, cortisol and testosterone were detected in low amounts. The results show that the 2-OHE2-induced GVBD response seems to be mediated through the production of 17,20β-P and corticosteroids. It is suggested that hydroxyoestrogens seem to be a component in the gonadotrophin cascade of regulation of oocyte maturation/ovulation in the catfish.

312 EFFECTS OF TRANSFORMING GROWTH FACTOR ALPHA AND INSULIN-LIKE GROWTH FACTOR 1 SUPPLEMENTATION ON IN VITRO MATURATION OF CANINE OOCYTES

2015 ◽  
Vol 27 (1) ◽  
pp. 245
Author(s):  
A. Sato ◽  
B. Sarentonglaga ◽  
K. Ogata ◽  
M. Yamaguchi ◽  
A. Hara ◽  
...  
Keyword(s):  
Growth Factor ◽  
Synergistic Effect ◽  
Oocyte Maturation ◽  
In Vitro Maturation ◽  
Transforming Growth Factor ◽  
Germinal Vesicle ◽  
Control Group ◽  
Insulin Like Growth Factor ◽  
Treatment Groups

Although in vitro maturation (IVM) of oocytes has been successfully established for many species, the efficiency of IVM in canine oocytes is still very low. As growth factors have been shown to promote oocyte maturation in some species, we investigated whether use of transforming growth factor α (TGF-a) and insulin-like growth factor 1 (IGF-1) might overcome the difficulties of achieving meiotic maturation in cultured canine cumulus-oocyte complexes (COC). Ovaries were obtained from bitches at 6 months to 7 years of age by ovariohysterectomy and were sliced repeatedly to release COC. In the first experiment, the COC were cultured at 38.8°C for 48 h in 5% CO2 in air in medium 199 supplemented with either TGF-a (0, 1, 10, or 100 ng mL–1) or IGF-1 (0, 0.5, 5, 10, or 50 µg mL–1). In the second experiment, the synergistic effect of TGF-a and IGF-1 was investigated by culturing COC in medium 199 supplemented with both TGF-a (0, 1, 10, or 100 ng mL–1) and IGF-1 (0, 0.5, 5, 10, or 50 µg mL–1). At the end of the culture period, the oocytes were denuded of cumulus cells by pipetting with a fine bore glass pipette; the denuded oocytes were then fixed in Carnoy's solution and stained with Hoechst 33342. The nuclear configuration and chromatin morphology of the oocytes were evaluated under confocal laser scanning microscopy. The cells were assigned to 1 of the following meiotic stages: germinal vesicle (GV), germinal vesicle breakdown (GVBD), metaphase I (MI), or metaphase II (MII). Data were analysed by ANOVA with Fisher's PLSD test. In experiment 1, no significant difference were observed in the rates of cells maturing to the MI and MII stages, but that in the 10 ng mL–1 of TGF-a group (56.3%) were larger than in the other treatment groups (38.8–51.0%). The frequencies of MII stage cells in the 5, 10, and 50 µg mL–1 of IGF-1 treatment groups (9.8, 13.3, and 12.2%, respectively) were significantly higher than in the 0.5 µg mL–1 of IGF-1 group and the control group (5.3 and 2.2%, respectively). In experiment 2, the frequency of MI and MII cells in the control, 1 ng mL–1 of TGF-a plus 0.5 µg mL–1 of IGF-1, 10 ng mL–1 of TGF-a plus 5 µg mL–1 of IGF-1, 10 ng mL–1 of TGF-a plus 10 µg mL–1 of IGF-1, and 100 ng mL–1 of TGF-a plus 50 µg mL–1 of IGF-1 group were 44.1, 36.1, 63.5, 70.8, and 50.8%, respectively. The frequency of MII cells in the control group and the same treatment groups were 2.8, 7.2, 10.4, 15.3, and 10.8%, respectively. Both frequencies in the 10 ng mL–1 of TGF-a plus 10 µg mL–1 of IGF-1 group were significantly higher than in the control group. The TGF-a may act in a paracrine fashion on the surrounding granulosa cells, and IGF-1 may play multiple roles in cellular metabolism, proliferation, growth, and differentiation in canine oocyte maturation, as has been reported for many other species. In conclusion, these results demonstrate that a synergistic effect between TGF-a and IGF-1 produces an increased rate of in vitro maturation to the MI and MII stages in canine oocytes.

scholarly journals 316EFFECTS OF ESTRADIOL-17² AND PROGESTERONE SUPPLEMENT ON THE RESUMPTION OF MEIOSIS OF CANINE OOCYTES MATURED IN VITRO

2004 ◽  
Vol 16 (2) ◽  
pp. 277
Author(s):  
M.K. Kim ◽  
Y.H. Fibrianto ◽  
H.J. Oh ◽  
G. Jang ◽  
K.S. Lee ◽  
...  
Keyword(s):  
Oocyte Maturation ◽  
In Vitro Maturation ◽  
Culture Medium ◽  
Linear Models ◽  
Uv Light ◽  
Germinal Vesicle ◽  
Domestic Animal ◽  
Estradiol 17Β

In the bitch, oocytes are ovulated at the germinal vesicle (GV) stage and mature in the isthmus of the oviduct around 3 days after ovulation, it is not known what elements trigger the release of this meiotic arrest. Canine IVM has shown limited success with maturation rates, usually around 20% (MII) (Farstad W, 2000 Anim. Reprod. Sci. 60–61, 375–387). Estrogen and progesterone are suggested to play a significant role in causing oocyte resumption of meiosis and progression to MII stage. The purpose of this study was to investigate the role of estradiol-17β (E2) and progesterone (P4) during in vitro maturation of canine oocytes in serum-free tissue culture medium (TCM)-199. Canine oocytes collected from bitches were categorized into three groups based on estrous stages, follicular, luteal, or anestrus, at routine ovariohystrectomy. Oocytes were cultured in vitro in TCM-199 supplemented with E2, P4 or E2+P4 according to experimental design at 39°C in 5% CO2 and O2. After 72h of maturation culture, oocytes were denuded, fixed in a 3.7% paraformaldehyde solution for 10min, stained with Hoechst 33342 in glycerol, and observed under the UV light. Three groups of oocytes were cultured in TCM-199 supplemented with different concentrations (0, 0.1, 1.0 or 2.0μgmL−1) of E2 (Experiment 1, n=898, replications: 5) or P4 (0, 0.5, 1.0 or 2.0μgmL−1, Experiment 2, n=734, replications: 5). Multiple comparisons were implemented using Generalized Linear Models in the SAS 8.12 program. The rates of oocyte maturation to MII stage were higher (P&lt;0.05) in follicular stage oocytes cultured with 2μgmL−1 E2 (17.9%) compared to other supplement groups (0 to 7.6%). No differences (P&lt;0.05) in rate of MII stage oocytes among P4 supplement groups were observed. In Experiment 3, to investigate the combined effects of E2 and P4 on in vitro maturation, three groups of oocytes were cultured in TCM-199 supplemented with 2μgmL−1 E2 and various concentration of P4 (0, 0.5, 1.0 or 2.0μgmL−1, Experiment 3, n=1613, replications: 5). The rate of oocyte maturation to MII stage (11.5%) was higher (P&lt;0.05) in follicular stage oocytes cultured with 2μgmL−1 E2+2.0μgmL−1 P4 supplement compared to other supplement groups (0 to 6.4%). In conclusion, the present study demonstrated that E2 supplement in the culture medium increased maturation of canine oocyte to MII stage and that supplement of P4 alone did not promote oocyte maturation. However, P4 supplemented with E2 further promoted oocyte maturation in the follicular stage compared to E2 supplement alone, indicating that P4 acts synergistically with E2 on canine oocyte maturation in the presence of E2. From our results, we conclude that canine oocytes are exposed to high levels of P4 during maturation due to the preovulatory luteinization of canine follicles which gives rise to high intrafollicular as well as intratubal P4 concentrations-this is very different from the situation in oocytes from other domestic animal species. This study was supported by Biogreen 21-1000520030100000.

scholarly journals Regulation of 17α-Hydroxyprogesterone Production during Induced Oocyte Maturation and Ovulation in Amur Sturgeon (Acipenser schrenckii)

2022 ◽  
Vol 10 (1) ◽  
pp. 86
Author(s):  
Yuya Hasegawa ◽  
Ryohei Surugaya ◽  
Shinji Adachi ◽  
Shigeho Ijiri
Keyword(s):  
Oocyte Maturation ◽  
In Vitro Study ◽  
Hydroxysteroid Dehydrogenase ◽  
Mrna Levels ◽  
Pituitary Extract ◽  
Hydroxylase Activity ◽  
Amur Sturgeon ◽  
Lyase Activity ◽  
The Sturgeons

In several teleosts, 17α, 20β-dihydroxy-4-pregnen-3-one (DHP) has been identified as a maturation-inducing steroid. DHP is synthesized from 17α-hydroxyprogesterone (17OHP) by 17β-hydroxysteroid dehydrogenase type 12-like (hsd17b12L). Along with 3β-hydroxysteroid dehydrogenase/Δ5-4 isomerase (3β-HSD), 17α-hydroxylase and C17-20 lyase are associated with 17OHP production. This study aimed to determine the roles of Amur sturgeon hsd3b, P450c17-I (cyp17a1), and P450c17-II (cyp17a2) in 17OHP production and to examine their enzyme activity and mRNA expression pattern during oocyte maturation. In the sturgeons used in this study, hsd3b encoded 3β-HSD, cyp17a1 catalyzed 17α-hydroxylase production with C17-20 lyase activity, and cyp17a2 processed 17α-hydroxylase activity alone. In the ovarian follicles of individuals that underwent induced ovulation, hsd3b mRNA levels increased rapidly, cyp17a1 expression was downregulated, and cyp17a2 expression was upregulated during oocyte maturation. Finally, an in vitro study revealed that salmon pituitary extract (SPE) stimulation rapidly induced hsd3b expression, whereas cyp17a1 expression was downregulated. In vitro, cyp17a2 expression did not rapidly increase with SPE stimulation. This rapid upregulation of hsd3b during oocyte maturation was first observed in teleosts. It was suggested that hsd17b12L expression is upregulated after 17OHP production, which is regulated by hsd3b, cyp17a1, and cyp17a2, resulting in DHP production.

245 EXPRESSION AND FUNCTIONAL ROLE OF CELL DIVISION CYCLE 42 IN MOUSE OOCYTES MATURATION AND PRE-IMPLANTATION DEVELOPMENT

2006 ◽  
Vol 18 (2) ◽  
pp. 230
Author(s):  
X.-S. Cui ◽  
X.-Y. Li ◽  
N.-H. Kim
Keyword(s):  
Protein Synthesis ◽  
Cell Division ◽  
Mrna Expression ◽  
Oocyte Maturation ◽  
Germinal Vesicle ◽  
Cell Division Cycle ◽  
Mrna Levels ◽  
Mouse Oocytes

Cell division cycle 42 (Cdc42), a member of the Rho family of small guanosine triphosphatase (GTPase) proteins, regulates multiple cell functions, including motility, proliferation, apoptosis, and cell morphology. In order to gain insight into the role of Cdc42 in embryo development, we first characterized mRNA and protein levels of Cdc42 in mouse oocytes and early embryogenesis. We then examined the possible role of the gene in oocyte maturation and pre-implantation development using RNA interference analysis. The relative abundance of Cdc42 transcripts were measured by real time RT-PCR. After normalization with histone H2a mRNA levels, the mRNA expression of Cdc42 was abundant in immature oocytes and reduced slightly in zygotes and 2- to 8-cell stage embryos. The expression levels were significantly increased during the morula and blastocyst stages. Indirect immunocytochemistry showed protein synthesis of Cdc42 in oocytes and embryos of all stages. Introducing small interference RNA (siRNA) of Cdc42 into germinal vesicle stage oocytes or zygotes specifically reduce both mRNA expression and protein synthesis of Cdc42 in metaphase II stage oocytes and early embryos developing in vitro. Meiotic maturation was significantly reduced following siRNA injection into germinal vesicle stage oocytes. It is evident that actin distribution in siRNA treated blastocysts is morphologically abnormal following injection of siRNA for Cdc42. Injection of siRNA into zygotes did not influence cleavage, but significantly decreased in vitro development to morulae and blastocysts. While housekeeping genes such as tissue plasminogen activator were not altered by siRNA, wiskott-aldrich syndrome protein family 1 (WASP1) mRNA was down-regulated in the morula. Interestingly, mRNA of WASP1, tubulin alpha 1 (Tuba1), and actin-related protein 2/3 complex subunit V (Arpc5) increased at the blastocyst stage following siRNA injection. These results suggest that Cdc42 plays an important role during oocyte maturation and early pre-implantation development, likely through linkage with several other genes. This work was funded by a grant from National Research Laboratory Program in Korea.

169 Nuclear Maturation Kinetics and In Vitro Fecundation of Immature Bovine Oocytes Injected into Preovulatory Follicles

2018 ◽  
Vol 30 (1) ◽  
pp. 224
Author(s):  
L. M. S. Simoes ◽  
A. P. C. Santos ◽  
E. A. Lima ◽  
R. E. Orlandi ◽  
M. P. Bottino ◽  
...  
Keyword(s):  
Oocyte Maturation ◽  
Germinal Vesicle ◽  
Causative Factor ◽  
Nuclear Maturation ◽  
Preovulatory Follicles ◽  
Fertilization Capacity ◽  
Bovine Oocytes ◽  
Metaphase I

The objective was to evaluate in vitro nuclear maturation and fecundation kinetics of oocytes injected into preovulatory follicles of synchronized cows using the intra-follicular oocyte injection (IFOI) technique. In experiment 1, 438 immature abattoir-bovine cumulus–oocyte complexes (COC) of grades I, II, and III were randomly allocated to 1 of 3 groups: Matvitro (n = 111), COC matured in vitro for 22 h; Matvivo20 (n = 172) and Matvivo30 (n = 155), 30 oocytes were injected into each preovulatory follicle of pre-synchronized recipients. In Matvivo20, oocytes were matured for 19.8 ± 0.1 h and in Matvivo30, for 28.3 ± 0.1 h. All cows received 12.5 mg of LH (Lutropin, Bioniche, Canada) at IFOI (Matvivo20) or 10 h after IFOI (Matvivo30). Oocytes from Matvivo20 and Matvivo30 were aspirated 20 h after LH injection for assessment of oocyte maturation and recovery rates. Oocytes were evaluated according to maturation kinetics as germinal vesicle, metaphase I, anaphase I, telophase I, metaphase II, parthenogenetically activated, and degenerated (chromosomal aberrations, presence of diffuse or indefinite chromatin). In experiment 2, immature abattoir-bovine COC (n = 202) of grades I, II, and III were randomly distributed into 2 groups: Matvitro (n = 103), COC were matured and fertilized in vitro; Matvivo (n = 99), same as Matvivo20 protocol, and COC fertilized in vitro. Presumptive zygotes were evaluated as fertilized, unfertilized, or polyspermic. Statistical analyses were performed by the GLIMMIX procedure of SAS (SAS Institute Inc., Cary, NC, USA). Recovery rate was lower (P < 0.001) in Matvivo20 (52.9%, 91/172) compared with Matvivo30 (72.9%, 113/155). Germinal vesicle (P = 0.94), metaphase I (P = 0.98), anaphase I (P = 0.99), and telophase I (P = 0.20) rates were similar. However, there were differences in metaphase II [Matvitro: 81.0% (90/111)a, Matvivo20: 74.5% (35/47)a, and Matvivo30: 41.6% (32/77)b; P = 0.001], degenerate [Matvitro: 5.4% (6/111)c, Matvivo20: 21.3% (10/47)b and Matvivo30: 48.1% (37/77); P = 0.001] and parthenogenetically activated [Matvitro: 0.0% (0/111)b, Matvivo20: 0.0% (0/47)b and Matvivo30: 9.1% (7/77)a; P = 0.001]. Polyspermic (P = 0.18) and abnormal (P = 0.98) rates were similar. However, there was a higher rate (P = 0.05) of fertilized oocytes in Matvivo (60.6%, 60/99) than in Matvitro (46.6%, 48/103). In conclusion, oocyte maturation in vivo after IFOI for 20 h does not alter maturation kinetics and increases in vitro oocyte fertilization capacity. However, the 10-h increase in intra-follicular oocyte permanence decreased the proportion of viable oocytes. Thus, the oocyte maturation phase is not the limiting causative factor for the low IFOI-embryo production rates.

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