Cholesterol-induced in vitro maturation of oocytes of Acipenser stellatus, Xenopus laevis, and Rana temporaria

Skoblina, M. N.; Shmerling, Zh.G.; Kondratieva, O.T.

doi:10.1016/0016-6480(81)90334-8

Cited by 5 publications

(3 citation statements)

References 14 publications

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“…The implications of cholesterol for female reproduction have been suggested by different studies in various species (Skoblina et al, 1981;Shim et al, 2002;Bełtowski and Semczuk, 2010;Fujimoto et al, 2010;van Montfoort et al, 2014). Cholesterol is indispensable as a substrate for steroid hormone synthesis in the mammalian ovarian follicle.…”

Section: Lipoprotein Cholesterol As a Substrate For Ovarian Steroidog...mentioning

confidence: 99%

“…The cholesterol content in the oocyte seems to modulate maturation, fertilization, activation and embryo development (Skoblina et al, 1981;Shim et al, 2002;Buschiazzo et al, 2008;Buschiazzo et al, 2013;Marco-Jimenez et al, 2014;Yesilaltay et al, 2014). Buschiazzo et al showed that cholesterol depletion with methyl-beta-cyclodextrin (MβCD) in the mouse oocyte PM reduced in vitro fertilization and egg activation rates, which was associated with alterations in the structure of PM microdomains (Buschiazzo et al, 2013).…”

Section: Cholesterol Content and Distribution In Oocytes And Eggsmentioning

confidence: 99%

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Implications of High-Density Cholesterol Metabolism for Oocyte Biology and Female Fertility

Arias

Quiroz

Santander

et al. 2022

Front. Cell Dev. Biol.

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Cholesterol is an essential component of animal cells. Different regulatory mechanisms converge to maintain adequate levels of this lipid because both its deficiency and excess are unfavorable. Low cell cholesterol content promotes its synthesis and uptake from circulating lipoproteins. In contrast, its excess induces the efflux to high-density lipoproteins (HDL) and their transport to the liver for excretion, a process known as reverse cholesterol transport. Different studies suggest that an abnormal HDL metabolism hinders female fertility. HDL are the only lipoproteins detected in substantial amounts in follicular fluid (FF), and their size and composition correlate with embryo quality. Oocytes obtain cholesterol from cumulus cells via gap junctions because they cannot synthesize cholesterol de novo and lack HDL receptors. Recent evidence has supported the possibility that FF HDL play a major role in taking up excess unesterified cholesterol (UC) from the oocyte. Indeed, genetically modified mouse models with disruptions in reverse cholesterol transport, some of which show excessive circulating UC levels, exhibit female infertility. Cholesterol accumulation can affect the egg´s viability, as reported in other cell types, and activate the plasma membrane structure and activity of membrane proteins. Indeed, in mice deficient for the HDL receptor Scavenger Class B Type I (SR-B1), excess circulating HDL cholesterol and UC accumulation in oocytes impairs meiosis arrest and hinders the developmental capacity of the egg. In other cells, the addition of cholesterol activates calcium channels and dysregulates cell death/survival signaling pathways, suggesting that these mechanisms may link altered HDL cholesterol metabolism and infertility. Although cholesterol, and lipids in general, are usually not evaluated in infertile patients, one study reported high circulating UC levels in women showing longer time to pregnancy as an outcome of fertility. Based on the evidence described above, we propose the existence of a well-regulated and largely unexplored system of cholesterol homeostasis controlling traffic between FF HDL and oocytes, with significant implications for female fertility.

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Section: Lipoprotein Cholesterol As a Substrate For Ovarian Steroidog...mentioning

confidence: 99%

Section: Cholesterol Content and Distribution In Oocytes And Eggsmentioning

confidence: 99%

Implications of High-Density Cholesterol Metabolism for Oocyte Biology and Female Fertility

Arias

Quiroz

Santander

et al. 2022

Front. Cell Dev. Biol.

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show abstract

“…In frogs and fish, these steroids also appear to be critical regulators of oocyte maturation (28,29), which is defined as the resumption of meiosis from prophase I to metaphase II. Fish oocyte maturation is regulated by various hydroxylated progesterone metabolites (30,31), whereas testosterone may be an important physiologic mediator of Xenopus oocyte maturation (8).…”

Section: Discussionmentioning

confidence: 99%

Xenopus laevis Ovarian CYP17 Is a Highly Potent Enzyme Expressed Exclusively in Oocytes

Yang

Lutz

Hammes

2003

Journal of Biological Chemistry

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Progesterone has long been considered the primary mediator of Xenopus oocyte maturation. We have recently shown, however, that androgens, which are equal or more potent promoters of maturation and are present at higher levels in ovulating frogs, may also be playing an important physiologic role in mediating maturation. Here, we examined the role of CYP17, a key enzyme mediating sex steroid synthesis, in Xenopus ovarian androgen production. We found that the 17,20-lyase activities of Xenopus CYP17 exceeded the 17␣-hydroxylase activities in both the ⌬4 and ⌬5 pathways; thus, Xenopus CYP17 rapidly converted pregnenolone and progesterone to dehydroepiandrosterone (DHEA) and androstenedione, respectively. This remarkably robust activity exceeds that of CYP17 from most higher vertebrates, and likely explains why virtually no progesterone is detected in ovulating frogs. Additionally, ovarian CYP17 activity was present exclusively in oocytes, although all other enzymes involved in sex steroid production were expressed almost entirely in surrounding follicular cells. This compartmentalization suggests a "two-cell" model whereby Xenopus ovarian androgen production requires both follicular cells and oocytes themselves. The requirement of oocytes for ovarian androgen production further introduces the unusual paradigm whereby germ cells may be responsible for producing important steroids used to mediate their own maturation.The phenomenon of steroid-induced maturation of Xenopus oocytes has served as a model for studying cell cycle and nongenomic steroid signaling for several decades (1-5). During this time, progesterone has been considered the primary physiologic mediator of oocyte maturation, perhaps through interactions with classical progesterone receptors expressed in the oocyte (6, 7). We have recently shown, however, that testosterone, rather than progesterone, may be the primary physiologic mediator of Xenopus oocyte maturation (8). This dominant role of testosterone is evidenced by the observation that testosterone is a substantially more potent activator of oocyte maturation than progesterone, and that testosterone levels are significantly higher than progesterone (which is nearly undetectable) in the serum and ovaries of ␤-HCG 1 -stimulated frogs. In addition, we have shown that, in vitro, isolated oocytes rapidly convert exogenously added progesterone to the androgen androstenedione (AD), which is an equally potent promoter of maturation when compared with progesterone. These data suggest that both AD and progesterone are likely inducing maturation under in vitro conditions typical for "progesteronemediated" maturation.The high levels of ovarian testosterone in the absence of detectable progesterone imply that Xenopus ovaries are extremely efficient at metabolizing progesterone. Additionally, the ability of isolated oocytes to rapidly convert progesterone to androgens suggests that the oocytes themselves may be important contributors to progesterone metabolism in the ovary. To explain the lack of in vivo progeste...

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Oocyte maturation in white sturgeon, Acipenser transmontanus: some mechanisms and applications

Lutes

1985

Environ Biol Fish

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The ovaries of four pre-spawning white sturgeon females were sampled and their oocytes incubated in the presence of eight gonadotropin preparations, 21 steroids, a prostaglandin and a catacholamine. Among the gonadotropin preparations, acetone dried pituitary gland powder from white sturgeon, common carp and chum salmon (in decreasing order of potency) were capable of inducing oocyte maturation (germinal vesicle breakdown -GVBD), while human chorionic gonadotropin, pregnant mare's serum gonadotropin, equine luteinizing hormone, bullfrog gonadotropin, and a stellate sturgeon pituitary chromatographic fraction capable of inducing testosterone production in white sturgeon testicular tissue failed to elicit any oocyte maturation response. The progesterone derivatives were the most potent steroid inducers of GVBD, followed closely by several corticosteroids. In vitro incubation of white sturgeon oocytes, in the presence of a suitable steroid (progesterone), can be used as a diagnostic tool in screening out unresponsive females for induced spawning work. The two remaining compounds, prostaglandin F?;, and epinephrine, failed to cause ovulation in progesterone-matured white sturgeon oocytes.

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Cholesterol-induced in vitro maturation of oocytes of Acipenser stellatus, Xenopus laevis, and Rana temporaria

Cited by 5 publications

References 14 publications

Implications of High-Density Cholesterol Metabolism for Oocyte Biology and Female Fertility

Implications of High-Density Cholesterol Metabolism for Oocyte Biology and Female Fertility

Xenopus laevis Ovarian CYP17 Is a Highly Potent Enzyme Expressed Exclusively in Oocytes

Oocyte maturation in white sturgeon, Acipenser transmontanus: some mechanisms and applications

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