scholarly journals In vivo change in the germinal vesicle of the sow oocyte during the follicular phase before the ovulatory LH surge

1980 ◽  
Vol 20 (3A) ◽  
pp. 673-680 ◽  
Author(s):  
Marie-Christine DAGUET
Keyword(s):  
Germinal Vesicle ◽  
Follicular Phase ◽  
Lh Surge

Chromatin, microtubule and microfilament configurations in the canine oocyte

2006 ◽  
Vol 18 (8) ◽  
pp. 849 ◽  
Author(s):  
Yong-Xun Jin ◽  
Hyo-Sang Lee ◽  
Xi-Jun Yin ◽  
Xiang-Shun Cui ◽  
Il-Keun Kong ◽  
...  
Keyword(s):  
Germinal Vesicle ◽  
Follicular Phase ◽  
Meiotic Metaphase ◽  
Condensed Chromatin ◽  
Meiotic Maturation ◽  
Advanced Stage ◽  
Cytoplasmic Microtubules ◽  
Metaphase I

In the present study, we observed chromatin, microtubule and microfilament distribution in canine oocytes. The germinal vesicle (GV) chromatin of canine oocytes was classified into four configurations (GV-I, -II, -III and -IV) based on the degree of chromatin separation and condensation. Oocytes recovered from follicular phase ovaries had a greater amount (68%, P < 0.05) of GV-III or GV-IV chromatin than did those from non-follicular phase ovaries (35%). The majority (86.7%) of in vivo ovulated oocytes were at GV-IV. The rates of development to GV breakdown/metaphase I/metaphase II were higher in oocytes recovered from follicular ovaries than from non-follicular ovaries. Immunostaining results revealed cytoplasmic microtubules present in all GV-stage oocytes. Following GV breakdown, microtubular asters were produced from condensed chromatin. The asters appeared to be elongated, and encompassed condensed chromatin particles to form meiotic metaphase chromatin. Microfilaments were located in the cortex and around the GV. During meiotic maturation, a microfilament-rich area, in which the chromatin is allocated, was observed in the oocyte. Our results indicate that oocytes recovered from follicular ovaries were in an advanced stage of GV, and were more competent to complete maturation compared to those from non-follicular phase ovaries. Both microtubules and microfilaments are closely associated with reconstruction of chromatin during meiotic maturation in canine oocytes.

Nonspecific effects of oligodeoxynucleotide injection in Xenopus oocytes: a reevaluation of previous D7 mRNA ablation experiments

Development ◽  
1990 ◽  
Vol 110 (3) ◽  
pp. 769-779
Author(s):  
R.C. Smith ◽  
W.M. Bement ◽  
M.A. Dersch ◽  
E. Dworkin-Rastl ◽  
M.B. Dworkin ◽  
...  
Keyword(s):  
Protein Synthesis ◽  
Xenopus Oocytes ◽  
Cell Metabolism ◽  
Germinal Vesicle ◽  
Annulate Lamellae ◽  
Maternal Mrna ◽  
Nonspecific Effects ◽  
Abnormal Accumulation ◽  
Cellular Mrnas

Microinjection of oligodeoxynucleotides (ODNs) complementary to cellular mRNAs has been advanced as an experimental approach to degrade target mRNAs in vivo and thereby obtain information as to the function of their cognate proteins. It is shown here that ODNs can induce a variety of aberrations in cell metabolism and structure when injected into Xenopus oocytes. Examination of histological sections of ODN-injected oocytes revealed the frequent abnormal accumulation of heavily staining basophilic material in the area of the germinal vesicle (gv). Ultrastructural analysis detected further abnormalities including blebbing of the plasma membrane, anomalous cytoskeletal structures, hyperorganised annulate lamellae, hyperinvagination of the gv, and formation of irregular nucleoli within the gv. Analysis of newly synthesised proteins by [35S]methionine radiolabelling of oocytes demonstrated that ODN injection can trigger a general decrease in both label uptake and protein synthesis. Qualitative effects on protein synthesis could also be observed, particularly a decrease in synthesis of high molecular weight proteins. The severity of ODN-induced effects is dose-dependent and highly variable from ODN to ODN. The previously reported delay in progesterone-induced maturation observed in oocytes depleted of the maternal mRNA D7 by ODN-directed degradation (Smith R. C., Dworkin M. B. and Dworkin-Rastl E. (1988) Genes and Devpt. 2, 1296–1306) is most likely a result of nonspecific ODN effects in the oocyte. Oocytes injected with effective antisense D7 ODNs that do not display detectable side effects matured with normal kinetics.

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.

159 EFFECT OF 3-ISOBUTYL-1-METHYLXANTHINE (IBMX) ON THE GERMINAL VESICLE STAGE OF PORCINE OOCYTES DURING OOCYTE COLLECTION IN VITRO

2014 ◽  
Vol 26 (1) ◽  
pp. 193
Author(s):  
R. Appeltant ◽  
J. Beek ◽  
D. Maes ◽  
A. Van Soom
Keyword(s):  
Germinal Vesicle ◽  
Cyclic Adenosine Monophosphate ◽  
Adenosine Monophosphate ◽  
Cumulus Cells ◽  
Guanosine Monophosphate ◽  
Developmental Competence ◽  
Meiotic Arrest ◽  
Oocyte Collection

When using modern maturation conditions for in vitro maturation, pig oocytes yield ~20% blastocysts only. One problem is that cumulus cells, which are normally connected with the immature oocyte by cellular projections penetrating through the zona pellucida and with the oolemma via gap junctions, are prematurely losing these connections after the cumulus–oocyte complex is removed from the follicle. The oocyte possesses a type 3 phosphodiesterase, which degrades 3′,5′-cyclic adenosine monophosphate (cAMP), and this activity is inhibited by supply of 3′,5′-cyclic guanosine monophosphate (cGMP) to the oocyte via the cumulus cells. Consequently, cAMP levels, which are typically high during early stages of oocyte maturation in vivo, decrease, leading to spontaneous nuclear maturation and oocytes of low developmental competence. Therefore, the maintenance of these cumulus-oocyte connections is important to keep cAMP high and the oocyte under meiotic arrest. One way to prevent this drop in cAMP is using N6, 2′-o-dibutyryladenosine 3′,5′-cyclic monophosphate sodium (dbcAMP) that causes an arrest at germinal vesicle (GV) stage II (Funahashi et al. 1997 Biol. Reprod. 57, 49–53). Another option is collecting the oocytes in a medium containing the phoshodiesterase inhibitor, IBMX. The present study investigated the influence of IBMX on the progression of the GV of the oocyte after collection, just before the start of the maturation procedure. The GV stage was defined according to Sun et al. (2004 Mol. Reprod. Dev. 69, 228–234). In parallel with the findings on dbcAMP, we hypothesised an arrest at GV II by the presence of IBMX during collection. One group of oocytes were collected in HEPES-buffered TALP without IBMX (n = 375) and another group in the same medium containing 0.5 mM IBMX (n = 586). An average incubation time of 140 min was applied in both groups, and 3 replicates were performed. The proportions of oocytes before or at GV II and beyond GV II were compared in both groups using logistic regression analysis. The proportion of oocytes was included as dependent variable and group (IBMX addition or not) as independent variable. Replicate was also included in the model. The proportion of oocytes before or at GV II was not statistically significant between the group without and the group with IBMX (59.2 v. 58.7% respectively; P > 0.05). In conclusion, the use of IBMX during oocyte collection did not influence the state of the germinal vesicle of the oocyte during collection, indicating that IBMX did not cause a meiotic arrest in the oocytes during collecting in vitro.

scholarly journals Evidence That the LH Surge in Ewes Involves Both Neurokinin B–Dependent and –Independent Actions of Kisspeptin

Endocrinology ◽  
2019 ◽  
Vol 160 (12) ◽  
pp. 2990-3000 ◽  
Author(s):  
Robert L Goodman ◽  
Wen He ◽  
Justin A Lopez ◽  
Michelle N Bedenbaugh ◽  
Richard B McCosh ◽  
...  
Keyword(s):  
Follicular Phase ◽  
Crossover Design ◽  
Phase Model ◽  
Combined Effects ◽  
Neurokinin B ◽  
Lh Surge ◽  
Gnrh Secretion ◽  
Retrochiasmatic Area

Abstract Recent evidence has implicated neurokinin B (NKB) signaling in the retrochiasmatic area (RCh) of the ewe in the LH surge. To test this hypothesis, we first lesioned NK3R neurons in this area by using a saporin conjugate (NK3-SAP). Three weeks after bilateral injection of NK3-SAP or a blank control (BLK-SAP) into the RCh, an LH surge was induced by using an artificial follicular-phase model in ovariectomized ewes. NK3-SAP lesioned approximately 88% of RCh NK3R-containing neurons and reduced the amplitude of the estrogen-induced LH surge by 58%, an inhibition similar to that seen previously with intracerebroventricular (icv) infusion of a KISS1R antagonist (p271). We next tested the hypothesis that NKB signaling in the RCh acts via kisspeptin by determining whether the combined effects of NK3R-SAP lesions and icv infusion of p271 were additive. Experiment 1 was replicated except that ewes received two sequential artificial follicular phases with infusions of p271 or vehicle using a crossover design. The combination of the two treatments decreased the peak of the LH surge by 59%, which was similar to that seen with NK3-SAP (52%) or p271 (54%) alone. In contrast, p271 infusion delayed the onset and peak of the LH surge in both NK3-SAP– and BLK-SAP–injected ewes. Based on these data, we propose that NKB signaling in the RCh increases kisspeptin levels critical for the full amplitude of the LH surge in the ewe but that kisspeptin release occurs independently of RCh input at the onset of the surge to initiate GnRH secretion.

Improved in vitro embryo development using in vivo matured oocytes from heifers superovulated with a controlled preovulatory lh surge

1999 ◽  
Vol 52 (2) ◽  
pp. 335-349 ◽  
Author(s):  
E.E. van de Leemput ◽  
P.L.A.M. Vos ◽  
E.C. Zeinstra ◽  
M.M. Severs ◽  
G.C. van der Weijden ◽  
...  
Keyword(s):  
Embryo Development ◽  
Lh Surge

scholarly journals Identification of androgen receptor phosphorylation in the primate ovary in vivo

Reproduction ◽  
2010 ◽  
Vol 140 (1) ◽  
pp. 93-104 ◽  
Author(s):  
Iain J McEwan ◽  
Dagmara McGuinness ◽  
Colin W Hay ◽  
Robert P Millar ◽  
Philippa T K Saunders ◽  
...  
Keyword(s):  
Endothelial Cells ◽  
Androgen Receptor ◽  
Granulosa Cells ◽  
Gnrh Antagonist ◽  
Follicular Phase ◽  
Surface Epithelium ◽  
Control Group ◽  
Target Tissue ◽  
Receptor Phosphorylation

The androgen receptor (AR) is a member of the nuclear receptor superfamily, and is important for both male and female reproductive health. The receptor is a target for a number of post-translational modifications including phosphorylation, which has been intensively studied in vitro. However, little is known about the phosphorylation status of the receptor in target tissues in vivo. The common marmoset is a useful model for studying human reproductive functions, and comparison of the AR primary sequence from this primate shows high conservation of serines known to be phosphorylated in the human receptor and corresponding flanking amino acids. We have used a panel of phosphospecific antibodies to study AR phosphorylation in the marmoset ovary throughout the follicular phase and after treatment with GNRH antagonist or testosterone propionate. In normal follicular phase ovaries, total AR (both phosphorylated and non-phosphorylated forms) immunopositive staining was observed in several cell types including granulosa cells of developing follicles, theca cells and endothelial cells lining blood vessels. Receptor phosphorylation at serines 81, 308, and 650 was detected primarily in the granulosa cells of developing follicles, surface epithelium, and vessel endothelial cells. Testosterone treatment lead to a modest increase in AR staining in all stages of follicle studied, while GNRH antagonist had no effect. Neither treatment significantly altered the pattern of phosphorylation compared to the control group. These results demonstrate that phosphorylation of the AR occurs, at a subset of serine residues, in a reproductive target tissue in vivo, which appears refractory to hormonal manipulations.

Source of ovarian inhibin secretion during the oestrous cycle of the sheep

1989 ◽  
Vol 123 (2) ◽  
pp. 181-188 ◽  
Author(s):  
G. E. Mann ◽  
A. S. McNeilly ◽  
D. T. Baird
Keyword(s):  
Corpus Luteum ◽  
Luteal Phase ◽  
Venous Blood ◽  
Contralateral Side ◽  
Follicular Phase ◽  
Oestrous Cycle ◽  
Secretion Rate ◽  
Antral Follicles ◽  
Luteal Tissue

ABSTRACT The source of inhibin secretion by the ovary in the sheep at different stages of the oestrous cycle was investigated by in-vivo cannulation of the ovarian veins. Twenty-four Scottish Blackface ewes were allocated to four groups of six ewes, i.e. those operated on during the luteal phase (day 10), and those operated on during the follicular phase 24–30, 36 and 60 h following an injection of 125 μg cloprostenol on day 10 of the luteal phase. Samples of jugular and timed ovarian venous blood were collected under anaesthesia before and after enucleation of the corpus luteum. Ovaries were then removed and follicles dissected out. Following injection of cloprostenol, luteal regression occurred as indicated by a fall in the secretion of progesterone. The concentration of inhibin in jugular venous plasma and its ovarian secretion rate were similar at all stages of the follicular phase and during the luteal phase. In contrast, the secretion rate of oestradiol rose from 2·68 ±0·73 pmol/min during the luteal phase to 8·70± 2·24 pmol/min 24 h after injection of cloprostenol (P<0·05). Following enucleation of the corpus luteum the secretion rate of progesterone fell from 809 ± 270 pmol/min to 86 ± 30 pmol/min (P<0·001). There was also a smaller, artifactual fall in the secretion rate of oestradiol following enucleation of the corpus luteum, which was of similar size to a fall seen in the secretion rate of inhibin. This resulted in a significant (P<0·001) fall in the ratio of progesterone to inhibin, while the oestradiol to inhibin ratio remained unchanged. The secretion rate of inhibin from ovaries containing luteal tissue was similar to that from the contralateral side without luteal tissue (1·41±0·30 compared with 1·32±0·30 ng/min), while ovaries with large antral follicles secreted significantly (P< 0·001) more inhibin than those with no follicles ≥3 mm (2·28 ± 0·36 compared with 0·25 ±0·06 ng/min). From these results we conclude that, in the sheep, large antral follicles are responsible for most, if not all, the secretion of inhibin by the ovary at all stages of the oestrous cycle, and that the corpus luteum secretes little or no immunoactive or bioactive inhibin. Due to the fact that, unlike inhibin, the secretion rate of oestradiol rises during the follicular phase of the cycle, when the concentration of FSH is suppressed, it seems likely that oestradiol rather than inhibin is the major ovarian factor modulating the change in FSH secretion seen at this stage of the oestrous cycle. Journal of Endocrinology (1989) 123, 181–188

Release of Glutamate and Aspartate from the Preoptic Area during the Progesterone-Induced LH Surge: In vivo Microdialysis Studies

1994 ◽  
Vol 59 (4) ◽  
pp. 318-324 ◽  
Author(s):  
Lin Ping ◽  
Virendra B. Mahesh ◽  
Vernon T. Wiedmeier ◽  
Drrell W. Brann
Keyword(s):  
Preoptic Area ◽  
In Vivo Microdialysis ◽  
Lh Surge
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