Inhibitory action of somatostatin on meiotic maturation of cultured porcine follicular ova

1985 ◽  
Vol 110 (3) ◽  
pp. 408-412 ◽  
Author(s):  
Takahide Mori ◽  
Minoru Irahara ◽  
Haruhiko Saito ◽  
Yoshio Ohno ◽  
Eiji Hosoi
Keyword(s):  
Inhibitory Action ◽  
Germinal Vesicle ◽  
Inhibitory Effect ◽  
Meiotic Maturation ◽  
Stimulatory Action ◽  
Germinal Vesicle Breakdown ◽  
Physiological Importance ◽  
Inhibiting Factor ◽  
Synthetic Oxytocin

Abstract. To investigate the physiological importance of somatotrophin release-inhibiting factor (SRIF), effects in vitro of synthetic SRIF 14 on germinal vesicle breakdown (GVB) of cultured porcine follicular ova were studied. The proportion of ova with GVB decreased gradually and significantly with increasing concentrations of SRIF 14 in the range from 6 × 10−12 to 6 × 10−7 m during a 22 h period of culture. The inhibitory effect was apparent for the period between 14 and 22 h in the course of culture but was reversed by a concomitant addition of anti-SRIF to the medium. Neither synthetic oxytocin, vasoactive intestinal polypeptide nor substance P exerted any inhibitory or stimulatory action on GVB. These results suggest a limited but definite inhibitory action of SRIF on GVB of porcine ova.

scholarly journals Aspects of cytoplasmic maturation of bovine oocytes: Interplay between mapk, mRNA-cap binding complex and cytoplasmic mRNA metabolism in regulation of translation

2003 ◽  
Vol 19 (3-4) ◽  
pp. 1-8 ◽  
Author(s):  
Tatjana Smiljakovic ◽  
Melo Sterza ◽  
M. Kubelka ◽  
Z. Vohnikova ◽  
W. Tomek
Keyword(s):  
Binding Protein ◽  
Germinal Vesicle ◽  
Initiation Factor ◽  
Meiotic Maturation ◽  
Detailed Knowledge ◽  
Germinal Vesicle Breakdown ◽  
Oocyte Growth ◽  
Stage Of Development ◽  
Bovine Oocytes

Bovine oocytes are arrested in the germinal vesicle stage (GV stage)and mature spontaneously when they are removed from their follicles and transferred to a suitable culture medium. This process, known as meiotic maturation is characterized among others, by germinal vesicle breakdown followed by metaphase I (MI) stage and further development to metaphase II (MII), where they become arrested again. During GVBD to MI transition, the overall protein synthesis reaches the highest level and it rapidly declines in MII. We have previously shown that transcription completely declines during meiotic maturation. Therefore we suppose that gene expression is exclusively regulated on translational level at this stage of development. This means that mRNAs, which were stored in repressed form during oocyte growth, were actively translated during meiotic maturation. Therefore we have investigated specific regulators of translation, namely the eukaryotic initiation factor of translation eIF4E (cap binding protein) and a specific repressor of eIF4E function, the 4E-binding protein 4E-BP1. Furthermore, we have elucidated pathways, which lead to eIF4E and 4E-BP1 phosphorylation by using specific M-phase kinase inhibitors, and we compare these results with transcription and cytoplasmic polyadenylation events during the course of meiotic maturation. The detailed knowledge of such regulatory processes can help to improve in vitro bio-techniques and to estimate the risk of these techniques.

scholarly journals Distribution of cortical granules and meiotic maturation of canine oocytes in bi-phasic systems

2015 ◽  
Vol 27 (7) ◽  
pp. 1082 ◽  
Author(s):  
Maricy Apparicio ◽  
Giuliano Q. Mostachio ◽  
Tathiana F. Motheo ◽  
Aracelle E. Alves ◽  
Luciana Padilha ◽  
...  
Keyword(s):  
In Vitro Maturation ◽  
Germinal Vesicle ◽  
Meiotic Maturation ◽  
Cortical Granule ◽  
Cortical Granules ◽  
Germinal Vesicle Breakdown ◽  
System A ◽  
Cytoplasmic Maturation ◽  
Positive Effect

The aim of this study was to evaluate the influence of different bi-phasic systems with gonadotrophins and steroids on in vitro maturation rates of oocytes obtained from bitches at different reproductive stages (follicular, luteal, anoestrous). In System A (control) oocytes were matured for 72 h in base medium (BM) with 10 IU mL–1 human chorionic gonadotrophin (hCG), 1 μg mL–1 progesterone (P4) and 1 μg mL–1 oestradiol (E2); in bi-phasic System B oocytes were matured for 48 h in BM with hCG and for 24 h in BM with P4; in bi-phasic System C oocytes were matured for 48 h in BM with hCG, P4 and E2, and for 24 h in BM with P4; in System D, oocytes were cultured in BM without hormonal supplementation. Data were analysed by ANOVA. There was a positive effect of the bi-phasic systems on germinal vesicle breakdown, metaphase I and metaphase II rates, irrespective of reproductive status (P < 0.05). Bi-phasic systems were also beneficial for cortical granule distribution (an indication of cytoplasmic maturation) and its relationship to nuclear status: 74.5% of the oocytes cultured in System B and 85.4% of those cultured in System C presented both nuclear and cytoplasmic maturation (P < 0.001). The stage of the oestrous cycle did not influence maturation rates.

scholarly journals Effects of the v-mos oncogene on Xenopus development: meiotic induction in oocytes and mitotic arrest in cleaving embryos.

1990 ◽  
Vol 111 (2) ◽  
pp. 533-541 ◽  
Author(s):  
R S Freeman ◽  
J P Kanki ◽  
S M Ballantyne ◽  
K M Pickham ◽  
D J Donoghue
Keyword(s):  
Antisense Oligonucleotide ◽  
Xenopus Oocytes ◽  
Kinase Activity ◽  
Germinal Vesicle ◽  
Mitotic Arrest ◽  
Meiotic Maturation ◽  
Germinal Vesicle Breakdown ◽  
Transforming Activity ◽  
Cytostatic Factor

Previous work has demonstrated that the Xenopus protooncogene mosxe can induce the maturation of prophase-arrested Xenopus oocytes. Recently, we showed that mosxe can transform murine NIH3T3 fibroblasts, although it exhibited only 1-2% of the transforming activity of the v-mos oncogene. In this study we have investigated the ability of the v-mos protein to substitute for the mosxe protein in stimulating Xenopus oocytes to complete meiosis. Microinjection of in vitro synthesized RNAs encoding either the mosxe or v-mos proteins stimulates resting oocytes to undergo germinal vesicle breakdown. Microinjection of an antisense oligonucleotide spanning the initiation codon of the mosxe gene blocked progesterone-induced oocyte maturation. When oocytes were microinjected first with the mosxe antisense oligonucleotide, and subsequently with in vitro synthesized v-mos RNA, meiotic maturation was rescued as evidenced by germinal vesicle breakdown. The v-mos protein exhibited in vitro kinase activity when recovered by immunoprecipitation from either microinjected Xenopus oocytes or transfected monkey COS-1 cells; however, in parallel experiments, we were unable to detect in vitro kinase activity associated with the mosxe protein. Microinjection of in vitro synthesized v-mos RNA into cleaving Xenopus embryos resulted in mitotic arrest, demonstrating that the v-mos protein can function like the mosxe protein as a component of cytostatic factor. These results exemplify the apparently conflicting effects of the v-mos protein, namely, its ability to induce maturation of oocytes, its ability to arrest mitotic cleavage of Xenopus embryo, and its ability to transform mammalian fibroblasts.

Meiotic maturation of mouse oocytes in vitro: inhibition of maturation at specific stages of nuclear progression

1976 ◽  
Vol 22 (3) ◽  
pp. 531-545
Author(s):  
P.M. Wassarman ◽  
W.J. Josefowicz ◽  
G.E. Letourneau
Keyword(s):  
Cyclic Amp ◽  
Cytochalasin B ◽  
Polar Body ◽  
Germinal Vesicle ◽  
Meiotic Maturation ◽  
Dibutyryl Cyclic Amp ◽  
Germinal Vesicle Breakdown ◽  
Mouse Oocytes ◽  
First Polar Body

In vitro studies of meiotic maturation of mouse oocytes have been carried out in the presence of several drugs. The individual steps of nuclear progression, including dissolution of the nuclear (germinal vesicle) membrane, condensation of dictyate chromatin into compact bivalents, formation of the first metaphase spindle, and extrusion of the first polar body, are each susceptible to one or more of these drugs. Germinal vesicle breakdown, the initial morphological feature characteristic of meiotic maturation, is inhibited by dibutyryl cyclic AMP. However, even in the presence of dibutyryl cyclic AMP, the nuclear membrane becomes extremely convoluted and condensation of chromatin is initiated but aborts at a stage short of compact bivalents. Germinal vesicle breakdown and chromatin condensation take place in an apparently normal manner in the presence of puromycin, Colcemid, or cytochalasin B. Nuclear progression is blocked at the circular bivalent stage when oocytes are cultured continuously in the presence of puromycin or Colcemid, whereas oocytes cultured in the presence of cytochalasin B proceed to the first meiotic metaphase, form an apparently normal spindle, and arrest. Emission of a polar body is inhibited by all of these drugs. The inhibitory effects of these drugs on meiotic maturation are reversible to varying degrees dependent upon the duration of exposure to the drug and upon the nature of the drug. These studies suggest that dissolution of the mouse oocyte's germinal vesicle and condensation of chromatin are not dependent upon concomitant protein synthesis or upon microtubules. On the other hand, the complete condensation of chromatin into compact bivalents apparently requires breakdown of the germinal vesicle. Failure of homologous chromosomes to separate after normal alignment on the meiotic spindle in the presence of cytochalasin B suggest that microfilaments may be involved in nuclear progression at this stage of maturation. Cytokinesis, in the form of polar body formation, is blocked when any one of the earlier events of maturation fails to take place.

scholarly journals Nucleus, Cytoskeleton, and Mitogen-Activated Protein Kinase p38 Dynamics during In Vitro Maturation of Porcine Oocytes

Animals ◽  
2019 ◽  
Vol 9 (4) ◽  
pp. 163
Author(s):  
Payungsuk Intawicha ◽  
Li-Kuang Tsai ◽  
Shih-Ying Yen ◽  
Neng-Wen Lo ◽  
Jyh-Cherng Ju
Keyword(s):  
Oocyte Maturation ◽  
Mammalian Cells ◽  
In Vitro Maturation ◽  
Germinal Vesicle ◽  
Mitogen Activated Protein Kinase ◽  
Meiotic Maturation ◽  
Germinal Vesicle Breakdown ◽  
Mitogen Activated Protein ◽  
Porcine Oocyte

The mitogen-activated kinase (MAPK) p38, a member of the MAPK subfamily, is conserved in all mammalian cells and plays important roles in response to various physiologic cues, including mitogens and heat shock. In the present study, MAPK p38 protein expression in porcine oocytes was analyzed during in vitro maturation (IVM) by Western blotting and immunocytochemistry. The levels of p-p38 or activated p38 and p38 expression were at the lowest in the germinal vesicle (GV) stage oocyte, gradually rising at the germinal vesicle breakdown (GVBD) and then reaching a plateau throughout the IVM culture (p < 0.05). Similarly, the expression level of total p38 was also lower in the GV oocyte than in the oocyte of other meiotic stages and uprising after GVBD and remained high until the metaphase III (MII) stage (p < 0.05). In the GV stage, phosphorylated p38 (p-p38) was initially detectable in the ooplasm and subsequently became clear around the nucleus and localized in the ooplasm at GVBD (18 h post-culture). During the metaphase I (MI) and metaphase II (MII) stages, p-p38 was evenly distributed throughout the ooplasm after IVM for 30 or 42 h. We found that the subcellular localization increased in p-p38 expression throughout oocyte maturation (p < 0.05) and that dynamic reorganization of the cytoskeleton, including microfilaments and microtubules, was progressively changed during the course of meiotic maturation which was likely to be associated with the activation or networking of p38 with other proteins in supporting oocyte development. In conclusion, the alteration of p38 activation is essential for the regulation of porcine oocyte maturation, accompanied by the progressive reorganization and redistribution of the cytoskeleton and MAPK p38, respectively, in the ooplasm.

scholarly journals Characterization of inhibin α subunit (inha) in the zebrafish: evidence for a potential feedback loop between the pituitary and ovary

Reproduction ◽  
2009 ◽  
Vol 138 (4) ◽  
pp. 709-719 ◽  
Author(s):  
Shui-Kei Poon ◽  
Wai-Kin So ◽  
Xiaobin Yu ◽  
Lin Liu ◽  
Wei Ge
Keyword(s):  
Feedback Loop ◽  
Transforming Growth Factor ◽  
Germinal Vesicle ◽  
Transforming Growth Factor Β ◽  
Inhibitory Effect ◽  
Follicle Cells ◽  
Germinal Vesicle Breakdown ◽  
Α Subunit ◽  
Vitellogenic Stage

Inhibin and activin are closely related disulphide-linked dimers that belong to the transforming growth factor β superfamily. Although inhibin has been extensively studied in mammals, the information about its existence and function in lower vertebrates is very scarce. Using zebrafish as a model, the present study demonstrated that the inhibin-specific α subunit (inha) was predominantly expressed in the gonads and no transcript could be detected in other tissues including the pituitary and brain. In the ovary, the expression ofinhawas restricted to the somatic follicle cells surrounding the oocyte, together with the β subunits (inhbaaandinhbb). This was further supported by the absence of its expression in the ovulated unfertilized eggs. During folliculogenesis,inhaexpression in the follicles slightly but steadily increased from primary growth to the mid-vitellogenic stage; however, its expression surged dramatically at the full-grown stage. Interestingly, the expression level ofinhadecreased significantly in the follicles whose oocytes were undergoing spontaneous maturation or germinal vesicle breakdown. When tested on cultured ovarian fragments, both goldfish pituitary extract and forskolin significantly stimulatedinhaexpression. Further experiments showed that recombinant zebrafish FSH but not LH significantly increasedinhaexpression in the same assay system. When testedin vitro, human inhibin A exhibited a slight but significant inhibitory effect on 17α, 20β-dihydroxyprogesterone-induced oocyte maturation after 4 h incubation. The stimulation ofinhaexpression by FSH and the potential inhibition of FSH by inhibin suggest a possible existence of a negative feedback loop between the pituitary and ovary in the zebrafish.

scholarly journals Independent activation of MAP kinase and MPF during the initiation of meiotic maturation in pig oocytes

Reproduction ◽  
2003 ◽  
pp. 645-656 ◽  
Author(s):  
J Ye ◽  
AP Flint ◽  
MR Luck ◽  
KH Campbell
Keyword(s):  
Map Kinase ◽  
Kinase Activity ◽  
Cumulus Cell ◽  
Germinal Vesicle ◽  
Kinase Assay ◽  
Meiotic Maturation ◽  
Significant Activity ◽  
Germinal Vesicle Breakdown ◽  
Domestic Species

Mitogen-activated protein (MAP) kinase is universally activated during oocyte maturation in all vertebrates studied to date. Its role in the resumption of meiosis and in the activation of maturation-promoting factor (MPF) remains unclear, especially in domestic species such as the pig. This study aimed to clarify the temporal and causal relationships between MAP kinase and MPF during meiotic maturation, particularly during the resumption of meiosis. Pig oocytes were matured synchronously in culture by treatment with cycloheximide. Kinase activities were analysed using a sensitive in vitro double-kinase assay and the specific MAP kinase pathway inhibitor U0126. MAP kinase and MPF were activated simultaneously at the time of germinal vesicle breakdown (GVBD; 6 h after removal of cycloheximide); they reached significant activity at 7 h (P < 0.05). The activities increased in parallel during GVBD (6-10 h) and peaked when the oocytes entered metaphase I (MI; 10 h). Whereas MAP kinase remained stable at peak activity thereafter, MPF activity significantly declined during the MI-MII transition (16-20 h) but increased to a second peak at MII (22 h). MAP kinase activity in denuded and cumulus-cell enclosed oocytes was completely inhibited by 20 and 80 mmicro mol U0126 l(-1), respectively. Oocytes without detectable MAP kinase activity underwent normal GVBD in terms of nuclear morphology and timing, although later meiotic stages were abnormal. The kinetics of MPF activity during GVBD were unaffected by U0126. This study has demonstrated that MAP kinase is activated simultaneously with MPF at GVBD, but that its activation is not essential for the activation of MPF nor for the resumption of the first meiosis in pig oocytes.

scholarly journals Luteinizing hormone-accelerated redistribution of lysosome-like organelles preceding dissolution of the nuclear envelope in rat oocytes maturing in vitro.

1979 ◽  
Vol 82 (1) ◽  
pp. 264-277 ◽  
Author(s):  
R M Ezzell ◽  
C M Szego
Keyword(s):  
Luteinizing Hormone ◽  
Nuclear Envelope ◽  
Germinal Vesicle ◽  
Defined Medium ◽  
Meiotic Maturation ◽  
Homogeneous Distribution ◽  
Target Cells ◽  
Specific Response ◽  
Germinal Vesicle Breakdown

Maturation of the mammalian oocyte is characterized in part by dissolution of the nuclear envelope, or germinal vesicle breakdown (GVB). By fluorescence microscopy after vital uptake of acridine orange (AO), redistribution and perinuclear accumulation of organelles corresponding to lysosomes occur before GVB in rat oocytes undergoing meiotic maturation in vitro. In follicle-enclosed oocytes explanted during the preovulatory gonadotropin surge (GS) and individually cultured as such in chemically defined medium at approximately 22 degrees C, lysosomes aggregated into disperse clusters after 30 min; by 60 min, perinuclear concentration of lysosomes and their essential disappearance from the cortical ooplasm were observed. GVB occurred within 120 min. In contrast, follicle-enclosed oocytes explanted before the GS displayed a generally homogeneous distribution of lysosomes and intact GV for up to 5 h in culture. In oocytes aspirated from follicles before the GS, partially denuded of granulosa cells, and cultivated without added hormone, most lysosomes concentrated around the GV within 60 min, with GVB occurring generally by 120 min. Luteinizing hormone (LH) added in vitro to the isolated preparation at 3 or 30 x 10(-8) M sharply accelerated these events. The effects of LH, not seen with 1.5 x 10(-8) M hormone, were blocked by anti-LH IgG. Up to 60 x 10(-8) M follicle-stimulating hormone or 80 x 10(-8) M prolactin were ineffective in accelerating lysosome redistribution or GVB. After GVB, lysosomes became once again uniformly dispersed and unresponsive, even to 60 x 10(-8) M added LH, a finding consistent with tachyphylaxis of target cells by independent criteria. The present data, all statistically significant at P less than 0.05, demonstrate that mobilization of lysosomes before GVB is a specific response to factors that promote resumption of meiotic maturation of rat oocytes.

Tyrosine phosphorylation of p34cdc2 and p42 during meiotic maturation of Xenopus oocyte. Antagonistic action of okadaic acid and 6-DMAP

Development ◽  
1991 ◽  
Vol 111 (3) ◽  
pp. 813-820 ◽  
Author(s):  
C. Jessus ◽  
H. Rime ◽  
O. Haccard ◽  
J. Van Lint ◽  
J. Goris ◽  
...  
Keyword(s):  
Tyrosine Phosphorylation ◽  
Okadaic Acid ◽  
Germinal Vesicle ◽  
Inhibitory Effect ◽  
Meiotic Maturation ◽  
Germinal Vesicle Breakdown ◽  
H1 Histone ◽  
Histone Kinase ◽  
Meiosis I

The tyrosine phosphorylation/dephosphorylation of p34cdc2 was estimated by immunoblotting with antiphosphotyrosine antibody during meiotic maturation of Xenopus oocytes. At the time of germinal vesicle breakdown (GVBD), p34cdc2 is tyrosine dephosphorylated whereas a p42 protein, which might correspond to a MAP2 kinase, becomes tyrosine phosphorylated. No modification in the level of tyrosine phosphorylation of either proteins was noticed during the whole maturation process from GVBD until metaphase II. When added to prophase oocytes, 6-DMAP (6-dimethyl-aminopurine) blocks GVBC, M-phase-promoting factor (MPF) activation and H1-histone, kinase activation induced by either progesterone, MPF transfer or okadaic acid microinjection. In each case, the tyrosine dephosphorylation reaction of p34cdc2 is inhibited. In meiosis I oocytes (just after the initiation of GVBD), 6-DMAP provokes the rephosphorylation of p34cdc2 on tyrosine residue(s), inactivation of MPF and H1-histone kinase and re-entry of the cell into an interphase-like state. These processes are reversible by simply removing the agent. In contrast to the observations in prophase oocytes, okadaic acid is able to reverse the inhibitory effect of 6-DMAP in meiosis I oocytes on MPF and H1-histone kinase activities and to initiate dephosphorylation of p34cdc2 on tyrosyl residue(s) even in the presence of 6-DMAP. Altogether, our results show that 6-DMAP and okadaic acid antagonistically control in vivo the level of tyrosine phosphorylation of p34cdc2.

Effect of mouse epidermal growth factor on DNA and protein synthesis, progesterone and inhibin production by bovine granulosa cells in culture

1986 ◽  
Vol 111 (1) ◽  
pp. 122-127 ◽  
Author(s):  
P. Franchimont ◽  
M. T. Hazee-Hagelstein ◽  
Ch. Charlet-Renard ◽  
J. M. Jaspar
Keyword(s):  
Protein Synthesis ◽  
Growth Factor ◽  
Epidermal Growth Factor ◽  
Granulosa Cells ◽  
Inhibitory Action ◽  
Inhibitory Effect ◽  
Stimulatory Action ◽  
Epidermal Growth ◽  
Dna And Protein Synthesis

Abstract. The effect of mouse epidermal growth factor (EGF) was investigated on DNA and protein synthesis, progesterone and inhibin production by bovine antral granulosa cells. When incubated for the whole period of culture, EGF inhibited inhibin production the second day of culture, progesterone the third and the fourth days whereas it stimulated DNA and protein synthesis only the fourth day of culture. Inhibition of progesterone and stimulation of DNA and protein were dose-dependent when treatment with EGF (pre-incubation) is followed by 24 h without EGF, a stimulatory effect on DNA and protein synthesis was observed after 48 and 72-h preincubation. Progesterone was reduced after 3 day preincubation and inhibin only after 2-day pre-incubation. Effects observed after 3-day pre-incubation were dosedependent. These experiments demonstrated the stimulatory effect of EGF on growth of granulosa cells and its inhibitory action on hormonal production by these cells in vitro. The inhibitory effect on progesterone and inhibin production is more precocious than stimulatory effect on DNA and protein synthesis. The inhibitory action of EGF on granulosa cell production of progesterone and inhibin could thus be not directly dependent on its stimulatory action on DNA synthesis.

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