scholarly journals Activity of key enzymes involved in glucose and triglyceride catabolism during bovine oocyte maturation in vitro

Reproduction ◽  
2002 ◽  
pp. 675-681 ◽  
Author(s):  
P Cetica ◽  
L Pintos ◽  
G Dalvit ◽  
M Beconi
Keyword(s):  
Enzymatic Activity ◽  
Pentose Phosphate Pathway ◽  
In Vitro Maturation ◽  
Specific Activity ◽  
Lipolytic Activity ◽  
Cumulus Cells ◽  
Pentose Phosphate ◽  
Key Enzymes ◽  
Glucose 6 Phosphate Dehydrogenase

Little is known about the metabolic profile of cumulus-oocyte complexes (COCs) during maturation. The aim of this study was to determine the differential participation of enzymatic activity in cumulus cells and the oocyte during in vitro maturation of bovine oocytes, by measuring the activity of key enzymes involved in the regulation of glycolysis (phosphofructokinase), the pentose phosphate pathway (glucose-6-phosphate dehydrogenase) and lipolysis (lipase). COCs were matured in medium 199 plus 10% (v/v) steer serum for 22-24 h at 39 degrees C in 5% CO(2):95% humidified air. Phosphofructokinase, glucose-6-phosphate dehydrogenase and lipase activities were measured in immature and in vitro matured COCs, denuded oocytes and cumulus cells, respectively. Phosphofructokinase and glucose-6-phosphate dehydrogenase activities (enzymatic units) remained constant during in vitro maturation of COCs, but there was a significant decrease in lipase activity (units) (P < 0.05), as activity in cumulus cells decreased significantly (P < 0.05). For the three enzymes studied, enzyme activity (units) remained unchanged in the oocyte during in vitro maturation. Specific activity increased in the oocyte (P < 0.05) and decreased in cumulus cells as a result of maturation (P < 0.05). In cumulus cells, phosphofructokinase was the most abundant of the three enzymes followed by glucose-6-phosphate dehydrogenase and then lipase (P < 0.05), whereas in the denuded oocyte this order was reversed (P < 0.05). Thus, the metabolism of cumulus cells is adapted to control the flow of metabolites toward the oocyte, which maintains its enzymatic activity even when dissociated from cumulus cells during maturation. The high activity of phosphofructokinase in cumulus cells indicates that glucose is metabolized mainly via the glycolytic pathway in these cells. The greater relative activity of glucose-6-phosphate dehydrogenase recorded in the oocyte indicates that glucose uptake could be directed mainly toward the pentose phosphate pathway. The marked lipolytic activity concentrated in the oocyte indicates an active participation in lipid catabolism during maturation.

343 DISTRIBUTION OF GLUCOSE-6-PHOSPHATE DEHYDROGENASE AND IN VITRO MATURATION OF PORCINE OOCYTE - CUMULUS COMPLEXES FROM SMALL AND MEDIUM FOLLICLES

2007 ◽  
Vol 19 (1) ◽  
pp. 287
Author(s):  
Y. Ishida ◽  
H. Funahashi
Keyword(s):  
In Vitro Maturation ◽  
Critical Role ◽  
Morphological Characteristics ◽  
Cumulus Cells ◽  
Pentose Phosphate ◽  
G6pd Activity ◽  
Cresyl Blue ◽  
Key Enzyme ◽  
Glucose 6 Phosphate Dehydrogenase

Glucose metabolism through the pentose phosphate pathway (PPP) plays a critical role in meiotic maturation and fertilization. However, the relationship between the distribution of a PPP key enzyme, glucose-6-phosphate dehydrogenase (G6PD), in cumulus–oocyte complexes (COCs) and the in vitro maturation (IVM) of the oocytes is not clear. In the present study, we examined the distribution of G6PD, the morphological characteristics in OCCs derived from small (d2 mm in diameter) and medium (3 to 6 mm in diameter) follicles, and the rate of oocyte maturation. Porcine COCs were collected from small or medium follicles of slaughterhouse ovaries. The COCs were cultured in a maturation medium, BSA-free NCSU37 supplemented with 10% porcine follicular fluid, eCG, and hCG, for 20 h and then in the absence of hormones for 24 h. To determine the distribution of G6PD, the COCs were treated with 13 �M brilliant cresyl blue (BCB) in TL-HEPES-PVA for 90 min. Results from 3–6 replicates were analyzed by ANOVA and Duncan&apos;s multiple range test. The mean diameters for COCs collected from small follicles (136.7 &micro;m for the outer zona and 103.1 &micro;m for ooplasm) were significantly less than for those derived from medium follicles (164.1 &micro;m and 122.0 &micro;m, respectively). G6PD activity was detected in the cumulus cells for most of the COCs derived from medium follicles, but it was not significantly different from that of COCs derived from small follicles. In the second group of COCs, very little G6PD activity was found in both the cumulus cells and the oocytes (34.7 &plusmn; 11.5&percnt; and 18.0 &plusmn; 6.7&percnt; in COCS derived from small and medium follicles, respectively). After stimulation by eCG and hCG, the percentages of COCS in which G6PD activity was detected in the cumulus cells, but not in the oocytes, were 56.2 &plusmn; 23.8&percnt; and 72.9 &plusmn; 6.1&percnt; for small and medium follicles, respectively. The percentage of oocytes at the metaphase II stage (53&percnt; and 63.9&percnt; in oocytes from small and medium follicles, respectively) was higher for the COCs that showed higher G6PD activity in their cumulus cells. In conclusion, although no statistical differences were detected in the distribution of G6PD between COCs from small and medium follicles, due to a large variation, a higher percentage of mature oocytes seems to be the result of COCs where the G6PD activity is detected in the cumulus cells, but not in the oocyte, during IVM.

scholarly journals 46 Effect of the addition of α-tocopherol to in vitro maturation media of bovine oocytes

2020 ◽  
Vol 98 (Supplement_2) ◽  
pp. 2-3
Author(s):  
Theisy P Acosta Pérez
Keyword(s):  
In Vitro Maturation ◽  
Cumulus Cells ◽  
Control Group ◽  
Chi Square ◽  
Cumulus Expansion ◽  
Minimum Concentration ◽  
Maturation Rate ◽  
Chi Square Test ◽  
System Data

Abstract α-tocopherol is known to be a powerful antioxidant, in this regard, it was added to bovine oocyte in vitro maturation media to evaluate its effect on oocyte maturation. Oocytes (n = 624) aspirated from ovaries of slaughtered cows were classified by quality and divided in four categories according to cytoplasm appearance and cumulus cells layers. Oocytes were washed in TCM-199 supplemented with fetal bovine serum (FBS) and FSH, then distributed in maturation media (TCM-199 supplemented with FBS, FSH and gentamicin). Three experimental groups of α-tocopherol (50, 100 and 200 mM) and a control group without α-tocopherol were used. Maturation was carried 22 h at 38.5°C in a 5% CO2 atmosphere. Oocytes were examined to determine cumulus expansion as categorical data (expansion or no expansion), as well as cumulus expansion Index (CEI). For CEI determination oocytes were graded 0 to 4, being 0 those with null expansion and 4 those with a noticeable cell expansion, then the number of oocytes were multiplied by the grade given and a sum of the totals was obtained, the new total was divided by the total of oocytes in the group and the result obtained corresponded to the CEI of the group. Results were analyzed with Chi Square test (for maturation rates) and an ANOVA (for the CEI) using the SAS system, data are presented as mean ± standard error. There was no statistical difference between control and α-tocopherol groups (P &gt;0.05). Numerically, the control group showed a higher maturation rate (100%) and obtained a higher CEI (2.44±0.20), followed by the 50 mM group (98.16%; 2.39±0.13), the groups 200 mM (97.40%; 2.00±0.14) and 100 mM (96.25%; 2.06±0.24) were the lowest. The addition of the minimum concentration (50 mM) of α-tocopherol to the maturation media could improve maturation rates without exposing oocytes to toxic effects.

Influence of cumulus cells on in vitro maturation and fertilization of equine oocytes

1996 ◽  
Vol 45 (1) ◽  
pp. 263 ◽  
Author(s):  
M.V. Marcos ◽  
A.R. Spell ◽  
M.D. Butine ◽  
M.J. Arns
Keyword(s):  
In Vitro Maturation ◽  
Cumulus Cells

scholarly journals Selection of Ovine Oocytes by Brilliant Cresyl Blue Staining

2012 ◽  
Vol 2012 ◽  
pp. 1-7 ◽  
Author(s):  
Liqin Wang ◽  
Jiapeng Lin ◽  
Juncheng Huang ◽  
Jing Wang ◽  
Yuncheng Zhao ◽  
...  
Keyword(s):  
Embryonic Stem ◽  
Cumulus Cells ◽  
Oocyte Quality ◽  
G6pd Activity ◽  
Blue Staining ◽  
Animal Cloning ◽  
Cresyl Blue ◽  
Deep Blue ◽  
Glucose 6 Phosphate Dehydrogenase

Sheep oocytes derived from the ovaries collected from the slaughterhouse are often used for research onin vitroembryo production, animal cloning, transgenesis, embryonic stem cells, and other embryo biotechnology aspects. Improving thein vitroculture efficiency of oocytes can provide more materials for similar studies. Generally, determination of oocyte quality is mostly based on the layers of cumulus cells and cytoplasm or cytoplasm uniformity and colors. This requires considerable experience to better identify oocyte quality because of the intense subjectivity involved (Gordon (2003), Madison et al. (1992) and De Loos et al. (1992)). BCB staining is a function of glucose-6-phosphate dehydrogenase (G6PD) activity, an enzyme synthesized in developing oocytes, which decreases in activity with maturation. Therefore, unstained oocytes (BCB−) are high in G6PD activity, while the less mature oocytes stains are deep blue (BCB+) due to insuffcient G6PD activity to decolorize the BCB dye.

Use of pregnancy‐associated plasma protein‐A during oocyte in vitro maturation increases IGF‐1 and affects the transcriptional profile of cumulus cells and embryos from Nelore cows

2019 ◽  
Vol 86 (11) ◽  
pp. 1694-1704
Author(s):  
Alan B. Giroto ◽  
Patrícia K. Fontes ◽  
Fernanda F. Franchi ◽  
Priscila H. dos Santos ◽  
Eduardo M. Razza ◽  
...  
Keyword(s):  
Plasma Protein ◽  
In Vitro Maturation ◽  
Protein A ◽  
Cumulus Cells ◽  
Transcriptional Profile

The effects of acetate and of pyruvate on the pathways of glucose catabolism in lactating mammary tissue. II. Sheep tissue

1969 ◽  
Vol 36 (3) ◽  
pp. 469-478 ◽  
Author(s):  
R. W. Smith ◽  
R. F. Glascock
Keyword(s):  
Pentose Phosphate Pathway ◽  
Acid Synthesis ◽  
Pentose Phosphate ◽  
Mammary Tissue ◽  
Glucose Catabolism ◽  
Glucose Carbon ◽  
Rat Tissue ◽  
The Relationship ◽  
Stimulation Of

SummaryA study was made of the changes in the rates of oxidation of the C(1), C(2) and C(6) atoms of glucose and in the pathways of glucose catabolism in sheep udder tissue in vitro which occurred when acetate and pyruvate were added.Whereas in rat mammary tissue the rate of oxidation of the C(1) atom of glucose was very much greater than that of the C(6) atom, the ratio of the rates of oxidation of these 2 atoms in sheep tissue was less than 2 when glucose was the only substrate.The addition of acetate resulted in an unequal stimulation of the oxidation of these 2 atoms, with the result that the ratio of their rates of oxidation was about doubled. The rate of oxidation of the C(2) atom was also increased.Acetate also increased the participation of the pentose phosphate pathway in glucose catabolism as measured by the incorporation of the C(1) and C(6) atoms of glucose into fatty acids, lactic acid and glycerol.Pyruvate produced little effect on the rate of oxidation of the C(1) atom but somewhat depressed that of the C(6) atom of glucose. At the same time, it caused a large increase in the participation of the pentose phosphate pathway.These results are discussed with reference to re-cycling of glucose carbon in the pentose phosphate pathway and to the relationship between that pathway and fatty acid synthesis. It is noted that the incorporation of glucose carbon into the 3 intermediates used gave values for the participation of that pathway which were in better agreement than was obtained in rat tissue. It is concluded that triose phosphates are more nearly in equilibrium in sheep than in rat mammary tissue.

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