A Quantitative and Cytological Study of Germ Cells in Human Ovaries

Baker, T. G.

doi:10.1097/00006254-196408000-00038

Cited by 118 publications

(165 citation statements)

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“…Fetal oocyte attrition (FOA) is the process of elimination of ~80% of the initial pool of human oocytes by the time of birth (Baker, 1963; Kurilo, 1981). This process is not unique to humans and has been observed in primates and extensively documented in several rodent species (Baker, 1966; Beaumont and Mandl, 1962; Burgoyne and Baker, 1985; Ioannou, 1964; McClellan et al, 2003).…”

Section: Introductionmentioning

confidence: 99%

A Role for Retrotransposon LINE-1 in Fetal Oocyte Attrition in Mice

et al. 2014

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SUMMARY Fetal oocyte attrition (FOA) is a conserved but poorly understood process of elimination of over two-thirds of meiotic prophase I (MPI) oocytes before birth. We now implicate retrotransposons LINE-1 (L1), activated during epigenetic reprogramming of the embryonic germline, in FOA in mice. We show that wild-type fetal oocytes possess differential nuclear levels of L1ORF1p, a L1-encoded protein essential for L1 ribonucleoprotein particle (L1RNP) formation and L1 retrotransposition. We demonstrate that experimental elevation of L1 expression correlates with increased MPI defects, FOA, oocyte aneuploidy and embryonic lethality. Conversely, reverse transcriptase (RT) inhibitor AZT has a profound effect on the FOA dynamics and meiotic recombination, and implicates an RT-dependent trigger in oocyte elimination in early MPI. We propose that FOA serves to select oocytes with limited L1 activity and therefore best suited for the next generation.

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Section: Introductionmentioning

confidence: 99%

A Role for Retrotransposon LINE-1 in Fetal Oocyte Attrition in Mice

et al. 2014

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“…Although several reports challenge the concept [47], [48], the prevailing notion is that the ovary harbours a finite quantum of follicular reserve, and no oocyte/follicle regeneration is possible in postnatal life [49]. However, in sharp contrast to the age-old belief that POI, like menopause, is associated with complete loss of follicular reserve and irreversible in nature, lines of evidence suggest that ∼ 50% of POI cases may be categorized under ovarian dysfunction type, who do have residual ovarian follicles despite the presence of elevated gonadotropins [50]–[51].…”

Section: Discussionmentioning

confidence: 99%

Female Reproductive Aging Is Master-Planned at the Level of Ovary

et al. 2014

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The ovary receives a finite pool of follicles during fetal life. Atresia remains the major form of follicular expenditure at all stages since development of ovary. The follicular reserve, however, declines at an exponential rate leading to accelerated rate of decay during the years preceding menopause. We examined if diminished follicle reserve that characterizes ovarian aging impacts the attrition rate. Premature ovarian aging was induced in rats by intra-embryonic injection of galactosyltransferase-antibody on embryonic day 10. On post-natal day 35 of the female litters, either a wedge of fat (sham control) or a wild type ovary collected from 25-day old control rats, was transplanted under the ovarian bursa in both sides. Follicular growth and atresia, and ovarian microenvironment were evaluated in the follicle-deficient host ovary and transplanted ovary by real time RT-PCR analysis of growth differentiation factor-9, bone morphogenetic protein 15, and kit ligand, biochemical evaluation of ovarian lipid peroxidation, superoxide dismutase (SOD) and catalase activity, and western blot analysis of ovarian pro- and anti-apoptotic factors including p53, bax, bcl2, and caspase 3. Results demonstrated that the rate of follicular atresia, which was highly preponderant in the follicle-deficient ovary of the sham-operated group, was significantly prevented in the presence of the transplanted ovary. As against the follicle-deficient ovary of the sham-operated group, the follicle-deficient host ovary as well as the transplanted ovary in the ovary-transplanted group exhibited stimulated follicle growth with increased expression of anti-apoptotic factors and down regulation of pro-apoptotic factors. Both the host and transplanted ovaries also had significantly lower rate of lipid peroxidation with increased SOD and catalase activity. We conclude that the declining follicular reserve is perhaps the immediate thrust that increases the rate of follicle depletion during the final phase of ovarian life when the follicle reserve wanes below certain threshold size.

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“…It is known that the primitive gonads of 45,X women contain germ cells (Singh and Carr, 1966); these are destroyed almost totally by the time of birth or soon afterwards, probably because of the failure of pre-granulosa cells to surround the germ cell and form primary follicles; germ cells not surrounded in this fashion, but left exposed to ovarian stroma, are quickly destroyed (Baker, 1963). This destruction is to some extent a normal process during intrauterine development and results in a reduction in the number of oocytes from almost 7 000 000 at the fifth month to around 2 000 000 at birth.…”

Section: Discussionmentioning

confidence: 99%

Fertility in 47,XXX and 45,X patients.

Dewhurst¹

1978

Journal of Medical Genetics

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SUMMARY Female patients with a sex chromosome abnormality may be fertile. In patients with a 47,XXX cell line there appears to be an increased risk of a cytogenetically abnormal child but the extent of this risk cannot yet be determined; it is probably lower in the non-mosaic 47,XXX patient than the mosaic 46,XX/47,XXX one. Patients with a 45,X cell line rarely become pregnant, and when they do they appear to have a high risk of an abnormal child or repeated unsuccessful pregnancies; this risk is certainly exaggerated by the method of reporting; when the poor reproductive performance is first identified leading to the recognition of the maternal cytogenetic fault, the reproductive failure rate is naturally high; when the maternal fault is first identified and the reproductive history then established far better results are evident.

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A Quantitative and Cytological Study of Germ Cells in Human Ovaries

Cited by 118 publications

References 0 publications

A Role for Retrotransposon LINE-1 in Fetal Oocyte Attrition in Mice

A Role for Retrotransposon LINE-1 in Fetal Oocyte Attrition in Mice

Female Reproductive Aging Is Master-Planned at the Level of Ovary

Fertility in 47,XXX and 45,X patients.

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