scholarly journals Steroid metabolism in vitro during final oocyte maturation in white croaker Micropogonias furnieri (Pisces: Scianidae)

2004 ◽  
Vol 64 (2) ◽  
pp. 211-220 ◽  
Author(s):  
J. García-Alonso ◽  
A. Nappa ◽  
G. Somoza ◽  
A. Rey ◽  
D. Vizziano
Keyword(s):  
Oocyte Maturation ◽  
Basic Knowledge ◽  
Enzymatic Oxidation ◽  
Steroid Synthesis ◽  
Fishery Resource ◽  
White Croaker ◽  
Final Oocyte Maturation ◽  
Micropogonias Furnieri ◽  
Derivatives Of

Final oocyte maturation (FOM) is a process involving a complex set of genetical, biochemical, and morphological mechanisms. FOM involves the shift of a post-vitellogenic follicle to a pre-ovulated oocyte, which is necessary for fertilization by spermatozoan to occur. This process is regulated by a maturation-inducing steroid (MIS) at the follicular level. In other species of scienids fish the MIS, a hydroxilated derivatives of progestagen 17, 20beta, 21-trihydroxy-4-pregnen-3-one (20beta-S), was identified. Although Micropogonias furnieri is the second fishery resource of Uruguay, basic knowledge about its endocrine process is very scarce. The aim of this work was to investigate what steroids are synthesized in vitro by the oocyte follicle of M. furnieri during the maturation process. Fragments of ovary (1 g) in three stages: post-vitellogenic (PV), maturing (Mtg), and mature (M) were incubated with 1 mug.g-1 of tritiated progesterone (P) at 30, 60, and 180 min. After extraction with ethanol and dichloromethane, steroid metabolites were purified by TLC and rpHPLC. Two progesterone derivatives with identical chromatographic properties of 20beta-S and 17,20beta-dihydroxy-4-pregnen-3-one (17,20beta-P) were purified. In other Teleost fish these steroids are biologically activ as MIS. The 17,20beta-P was clearly detected in Mtg and M stages and confirmed by enzymatic oxidation with enzyme 20beta-HSD. The 20beta-S was strongly detected in all Mtg oocytes. The results do not corroborate 20beta-S as a major hormone synthesized in the ovary in FOM as occurs in other scienid fish. A differential steroid synthesis in the advanced oocyte stages suggests that the 20beta-S is acting as a MIS in M. furnieri.

1 INSULIN TREATMENT DURING IN VITRO OOCYTE MATURATION LEADS TO DIFFERENT GENE EXPRESSION AND METHYLATION PATTERNS OF KEY GENES ASSOCIATED WITH METABOLISM AND STEROID SYNTHESIS IN THE BOVINE BLASTOCYST

2017 ◽  
Vol 29 (1) ◽  
pp. 108
Author(s):  
D. Laskowski ◽  
P. Humblot ◽  
M. A. Sirard ◽  
Y. Sjunnesson ◽  
G. Andersson ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Lipid Metabolism ◽  
Oocyte Maturation ◽  
Steroid Synthesis ◽  
Developmental Potential ◽  
Increased Risk ◽  
In Vitro Oocyte Maturation ◽  
Methylation Patterns ◽  
And Oxidative Stress

Obesity and overfeeding are common causes for female infertility, leading to insulin resistance and hyperinsulinemia and associated with an increased risk for type 2 diabetes mellitus (Pasquali et al., http://dx.doi.org/10.1093/humupd/dmg024). We investigated here the effect of insulin during in vitro oocyte maturation on methylation changes in bovine Day 8 blastocysts (BC8) and focused on methylation patterns of candidate genes associated with metabolism and steroidogenesis (Day 0 = day of oocyte collection). Abattoir-derived oocytes (n = 882) were in vitro matured for 22 h with 2 different insulin concentrations, INS10 (10 µg mL−1) and INS0.1 (0.1 µg mL−1) or without insulin (INS0, control). Subsequently, IVF and IVC were performed to equal standardized conditions for all groups. Parallel genomic DNA and total RNA extraction (AllPrepDNA/RNA micro kit, cat no. 80284, Qiagen®, Valencia, CA, USA) from pools of 10 frozen (−80°C) BC8 was followed by transcriptome and epigenome analysis (Laskowski et al., http://dx.doi.org/10.1071/RD15315). An empirical Bayes moderated t-test and the ‘limma’ package in R (www.r-project.org) were used to search for differentially expressed genes between the control and the insulin groups. Analysis of the epigenome by using a specific pipeline, described by Shojaei Saadi et al. (2014 BMC Genomics 15, 451), showed that 7632 and 3914 regions were hypomethylated in the INS0.1 and INS10 v. INS0, whereas 6026 and 8504 regions were hypermethylated in INS0.1 and INS10 v. INS0. Combining epigenetic and transcriptomic data, we found that high methylation and low expression or the reverse (low methylation and high expression) were observed for a set of 14 and 11 genes for INS0.1 and INS10 respectively. Most of these genes are associated with lipid metabolism, steroid synthesis, and oxidative stress. Further investigation of the localization of differentially methylated regions (DMR) in genes showed that the conservation odds (methylation) was in general higher in coding regions and CpG islands than in noncoding regions. We observed a large overlap of DMR in the 2 insulin groups compared with controls (3233 common DMR). These numerous changes illustrate the potential unfavourable effects of elevated insulin during maturation leading to alteration of the methylation patterns of the early embryo. This model may help us better understand the mechanisms by which metabolic disorders observed pre-conception can affect embryonic development and subsequent health of the offspring. Our results based on changes in transcriptome or epigenome did show that insulin challenge during maturation leads to postponed effects associated with steroidogenesis, lipid metabolism and oxidative stress in the BC8. By this early stage, if persistent, specific changes in the expression and methylation patterns of genes associated to hyperinsulinemia may decrease the developmental potential of early embryos or could be responsible for subsequent pathologies. This study was funded by FORMAS.

scholarly journals Pharmaceutical Options for Triggering of Final Oocyte Maturation in ART

2014 ◽  
Vol 2014 ◽  
pp. 1-7 ◽  
Author(s):  
Juan Carlos Castillo ◽  
Peter Humaidan ◽  
Rafael Bernabéu
Keyword(s):  
Oocyte Maturation ◽  
Paradigm Shift ◽  
Ovulation Induction ◽  
Human Reproduction ◽  
Prolonged Action ◽  
Follicular Maturation ◽  
Final Oocyte Maturation ◽  
Neuroendocrine Mechanisms ◽  
Hcg Trigger

Since the pioneering days ofin vitrofertilization, hCG has been the gold standard to induce final follicular maturation. We herein reviewed different pharmaceutical options for triggering of final oocyte maturation in ART. The new upcoming agent seems to be GnRHa with its potential advantages over hCG trigger. GnRHa triggering elicits a surge of gonadotropins resembling the natural midcycle surge of gonadotropins, without the prolonged action of hCG, resulting in the retrieval of more mature oocytes and a significant reduction in or elimination of OHSS as compared to hCG triggering. The induction of final follicular maturation using GnRHa represents a paradigm shift in the ovulation triggering concept in ART and, thus, a way to develop a safer IVF procedure. Kisspeptins are key central regulators of the neuroendocrine mechanisms of human reproduction, who have been shown to effectively elicit an LH surge and to induce final oocyte maturation in IVF cycles. This new trigger concept may, therefore, offer a completely new, “natural” pharmacological option for ovulation induction. Whether kisspeptins will be the future agent to trigger ovulation remains to be further explored.

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