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Anne Grete Byskov

Publications and source records attributed to Anne Grete Byskov.

18 recordsLinked to original sources
PubMed2006

Estradiol and regulation of anti-Müllerian hormone, inhibin-A, and inhibin-B secretion: analysis of small antral and preovulatory human follicles' fluid.

CONTEXT: In ovaries surgically removed for fertility preservation, hormone concentrations in fluid from small antral follicles were determined. Levels were compared with those found in preovulatory follicular fluid. OBJECTIVE: The objective of this study is to measure intrafollicular concentrations of anti-Müllerian hormone (AMH), inhibin-A, inhibin-B, estradiol, and progesterone. SETTING: The study was set in a university hospital. PATIENTS: Patients were 22 women suffering from a cancer disease and 16 women undergoing assisted reproduction. INTERVENTIONS: Fluid from 35 follicles (diameter, 3-8 mm) was included and compared with that of 32 preovulatory follicles. MAIN OUTCOME MEASURES: The main outcome measures were intrafollicular concentrations of the measured hormones and their possible correlation. RESULTS: Concentrations of AMH in small antral follicles were almost three orders of magnitude higher than in follicle fluid of preovulatory follicles, 790 +/- 95 vs. 1.17 +/- 0.14 ng/ml (mean +/- sem), respectively. There was a significant negative correlation between estradiol and AMH in fluid from small antral follicles, whereas inhibin-A and inhibin-B were correlated positively with estradiol concentrations. Progesterone showed a similar correlation to levels of AMH but only in fluid of preovulatory follicles. CONCLUSIONS: The high expression of AMH in granulosa cells of small antral follicles actually translates into very high follicle fluid AMH concentrations. This most likely explains the correlation between serum AMH levels and the number of small antral follicles as previously demonstrated. The negative correlation between estradiol and AMH suggests that FSH down-regulates AMH expression. Thus, the microenvironment of the follicle shows profound changes with developmental stage and highlights the importance of studies to understand the mechanisms that regulate follicular growth and development during antral stages of development.

Adolescent↗
PubMed2006

Ovulation jumping from the left to the right ovary in two successive cycles may increase the chances of pregnancy during intrauterine insemination and/or in vitro fertilization natural cycles.

Identification of the ovary from which ovulation takes place in two consecutive menstrual cycles results in one of four ovulation patterns, contralateral and ipsilateral ovulations on the right or on the left ovary. Our data suggest that IVF and IUI treatment in cycles in which development of the dominant follicle occurs in the right-sided ovary--and ovulation took place from the left-sided ovary in the preceding cycle (contralateral right-sided ovulation)--is likely to show the best pregnancy outcome.

Female↗
PubMed2006

Expression and localization of the progesterone receptor in mouse and human reproductive organs.

The effects of gonadotropins on progesterone receptor (PR) expression and localization in the mouse oviduct, uterus, and ovary was examined. In the oviduct ciliated epithelial cells of adult mice and human revealed a unique PR localization to the lower half of the motile cilia whereas the nuclei were unstained or faintly stained. Pubertal female mice were further studied by confocal laser scanning microscopy and western blotting before and after injection with FSH and LH followed by human chorionic gonadotropin (hCG) injection after a 48-h period. PR immunolocalization to the oviduct cilia was greatly increased in pubertal mice upon hCG stimulation. In neighboring goblet cells, the PR staining was confined to the nuclei. Nuclear PR localization was evident in epithelial cells of the uterus as well as in a fraction of stromal and muscle cells. Staining intensity and number of stained cells was not affected by hormone stimulation. In the ovary, weak PR immunolocalization was observed in unprimed animals but increased significantly after hCG stimulation. In granulosa cells of preovulatory follicles PR was exclusively observed in mural cells, whereas cumulus cells remained negative. At all stages examined, primary granulosa cell cilia lacked PR staining. SDS-PAGE and western blotting analysis of tissues from oviduct, uterus, and ovary confirmed antibody specificity, and identified two bands corresponding to the PR isoforms PR-A and PR-B. Upon hCG stimulation, a new band cross-reacting with anti-PR emerged above the PR-A form in oviduct fractions, suggesting LH-induced phosphorylation of PR-A. We suggest that ciliary PR in the oviduct plays a role in progesterone signaling after ovulation, possibly via non-genomic events. These novel findings warrant further studies of oviduct and postovulatory signaling events and suggest a sensory role for oviduct cilia in the process of oocyte transport/fertilization.

Adult↗
PubMed2005

Stem cell factor and c-Kit in human primordial germ cells and fetal ovaries.

The distribution of the tyrosine kinase receptor c-Kit and its ligand stem cell factor (SCF) was evaluated by immunohistochemistry in primordial germ cells (PGCs) and human embryonic gonads during weeks 5-8 of prenatal life, and fetal ovaries during weeks 9-36 of prenatal life. Distinct c-Kit and SCF staining was present in primordial germ cells in the wall of the hindgut and in the dorsal mesentery, particularly on level with the 10th thoracic columnar segment. Several PGCs were in close contact with c-Kit-negative but SCF-positive autonomic nerve fibers of the dorsal mesentery. Many fibroblasts and mesothelial cells of the dorsal mesentery were clearly stained for SCF, but not for c-Kit. Prominent c-Kit and SCF staining was present in germ cells of the embryonic gonadal anlage and in oogonia during further ovarian development. However, oocytes were either unstained or faintly stained for SCF. Oocytes not yet enclosed in follicles or present in primordial follicles were either unstained or exhibited faint cytoplasmic c-Kit staining, whereas oocytes of growing preantral follicles again showed distinct cell membrane staining which decreased during further follicular growth. Theca cells did not stain for c-Kit. Some pregranulosa cells and the first formed granulosa cells of primordial follicles were c-Kit stained. Granulosa cells of other follicles were not c-Kit stained. In the inner part of the cortex, SCF immunolabeling was detected in some pregranulosa cells surrounding cords containing germ cells and involved in formation of primordial follicles. Granulosa cells of primordial and growing follicles, including medium-sized antral follicles also revealed SCF staining. In conclusion, this first report on SCF in human PGCs and embryonic and fetal ovaries together with the c-Kit data lend substantial countenance to the notion that c-Kit and SCF play important roles during ascent of primordial germ cells towards the gonadal anlage, and during oogenesis and folliculogenesis in the human fetal ovary. We suggest that both autocrine and paracrine mechanisms are involved in the proposed anti-apoptotic effect of the c-Kit/SCF duet while PGCs are present in the dorsal mesentery. The SCF-positive autonomic nerve fibers of the dorsal mesentery, mesothelial cells and fibroblasts may nurse and perhaps guide PGCs during their ascent.

Female↗
PubMed2005

Localization of transient receptor potential ion channels in primary and motile cilia of the female murine reproductive organs.

We have examined the subcellular localization of transient receptor potential (TRP) ion channels and the potential sensory role of cilia in murine female reproductive organs using confocal laser scanning microscopy analysis on ovary and oviduct tissue sections as well as on primary cultures of follicular granulosa cells. We show that the Ca2+ permeable cation channel, polycystin-2, as well as polycystin-1, a receptor that forms a functional protein complex with polycystin 2, distinctively localize to primary cilia emerging from granulosa cells of antral follicles in vivo and in vitro. Both polycystins are localized to motile oviduct cilia and this localization is greatly increased upon ovulatory gonadotropic stimulation. Further, the Ca2+ permeable cation channel, TRP vaniloid 4 (TRPV4), localizes to a sub-population of motile cilia on the epithelial cells of the ampulla and isthmus with high intensity in proximal invaginations of the epithelial folds. These observations are the first to demonstrate ciliary localization of TRP ion channels and their possible receptor function in the female reproductive organs. We suggest that polycystins 1 and 2 play an important role in granulosa cell differentiation and in development and maturation of ovarian follicles. In the oviduct both TRPV4 and polycystins could be important in relaying physiochemical changes in the oviduct upon ovulation.

Animals↗
PubMed2005

Eggs forever?

A group of scientists from Harvard Medical School (Johnson et al., 2004) claims to have "established the existence of proliferative germ cells that sustain oocyte and follicle production in the postnatal mammalian ovary," expressing no doubts about their methods, results and conclusion. Johnson et al. based their conclusions of oocyte and follicular renewal from existing germline stem cells (GSC) in the postnatal mouse ovary on three types of observations: (1) A claimed discordance in follicle loss versus follicle atresia in the neonatal period and in the following pubertal and adult period; (2) immunohistochemical detection of proliferating GSC with meiotic capacity using combined markers for meiosis, germline, and mitosis; and (3) neo-folliculogenesis in ovarian chimeric grafting experiments with adult mice. Oogenesis is the process that transforms the proliferative oogonium into an oocyte through meiosis, followed by folliculogenesis and follicular and oocyte maturation. The most crucial part in producing a functional oocyte is firstly, initiation and completion of the first meiotic prophase, and secondly, enclosure of the resulting diplotene oocyte in a follicle. Neither of these two events has been shown to take place in Johnson et al.'s study of the postnatal mouse ovary. We hereby address the observations underpinning their hypothesis and conclude that it is premature to replace the paradigm that adult mammalian neo-oogenesis/folliculogenesis does not take place.

Animals↗
PubMed2005

Expression of IGF-II mRNA-binding proteins (IMPs) in gonads and testicular cancer.

Insulin-like growth factor-II mRNA-binding proteins 1, 2 and 3 (IMP1, IMP2 and IMP3) belong to a family of RNA-binding proteins implicated in mRNA localization, turnover and translational control. We examined their expression pattern during development of murine and human testis and ovaries. In the mouse, IMPs were expressed in male and female gonadal cells at embryonic day 12.5 (E12.5). From E16.5, IMP1 and IMP3 became restricted to the developing germ cells, whereas IMP2 expression persisted in the interstitial cells. In mature mouse and human ovaries, IMP1, IMP2 and IMP3 were detected in resting and growing oocytes and in the granulosa cells. In testis, IMP1 and IMP3 were found mainly in the spermatogonia, whereas IMP2 was expressed in the immature Leydig cells. Moreover, all three IMPs were detected in human semen. The developmental expression pattern of IMP1 and IMP3 in the human testis prompted us to examine their possible involvement in testicular neoplasia. IMPs were detected primarily in germ-cell neoplasms, including preinvasive testicular carcinoma in situ, classical and spermatocytic seminoma, and nonseminomas, with particularly high expression in undifferentiated embryonal carcinoma. The relative expression of IMP1, IMP2 and IMP3 varied among tumor types and only IMP1 was detected in all carcinoma in situ cells. Thus IMPs, and in particular IMP1, may be useful auxiliary markers of testicular neoplasia.

Animals↗
PubMed2004

Roles of gonadotropins and meiosis-activating sterols in meiotic resumption of cultured follicle-enclosed mouse oocytes.

This study describes a model for short-term culture of intact mouse follicles under serum-free conditions. Follicles were either obtained from immature mice receiving no ovarian stimulation (i.e. no eCG-primed protocol, group I) or from mice undergoing ovarian stimulation (i.e. eCG-primed protocol, group II). Follicles were grouped according to size (100-170, 180-200, 210-250, 260-350 and 360-400 microm, respectively) and cultured for 24h (group I) or for only 6h (group II). Induced meiotic resumption of follicle-enclosed oocytes were evaluated following stimulation with gonadotropins (i.e. FSH and hCG), AY9944-A-7, an inhibitor of Delta14-reductase, and RS-21745, an inhibitor of lanosterol 14alpha-demethylase; both enzymes affect synthesis of the meiosis activating sterols (MAS) that induce oocyte maturation. The frequency of oocyte degeneration was also recorded. In group I, FSH (10-200 IUl-1) and AY9944-A-7 (5, 25 and 50 microM) separately induced resumption of meiosis in oocytes derived from follicles with a diameter of 180-400 microm. hCG (1.0 and 10 IUml-1) exhibited a similar but weaker effect on oocytes present in follicles with a diameter of 260-400 microm. Irrespective of follicular diameter oocytes obtained from follicles in group II responded to hCG and FSH by resuming meiosis. FSH (50 IUl-1) alone or hCG (10 IUml-1) alone both increased the GVBD percentage of oocytes enclosed in follicles with a diameter 260-400 microm, but the response to hCG was not significant compared to control. FSH (50 IUl-1) combination with hCG (10 IUml-1) showed an additive effect raising the rate of GVBD after 6h culture. Addition of 50 or 100 microM RS-21745 was able to attenuate gonadotropins-induced resumption of meiosis to below background levels. In conclusion, the ability of FSH to induce meiotic resumption of follicle-enclosed mouse oocytes is correlated to follicle size, being most pronounced in larger follicles. hCG caused a similar but less pronounced effect. The ability of RS-21745 to inhibit and the ability of AY9944-A-7 to enhance oocyte maturation of follicle-enclosed oocytes support the concept of FSH employing MAS as a downstream signal transduction molecule for initiation of oocyte maturation in mice.

Aniline Compounds↗
PubMed2004

Tesmin transcription is regulated differently during male and female meiosis.

Tesmin is a protein with homology to the metal-binding motif of the metallothionein protein family. Tesmin has been described as a testis-specific transcript, which starts to accumulate in 8-day-old mouse spermatocytes. Herein, a differential display comparing meiotic gene expression in embryonic ovaries and mature testes also revealed the presence of the Tesmin transcript in fetal ovaries as well as in fetal and adult heart. Time-course experiments showed that Tesmin was expressed in a characteristic development-related manner in fetal ovaries. Only a weak expression was observed at E12(1/2), the strongest signal was reached at E14(1/2), whereas the signal declined between E14(1/2) and E16(1/2). This transitional expression coincides with the early stages of the female meiotic prophase I. In the male, however, Tesmin was expressed in all stages of meiotic prophase I except preleptonema and leptonema. In situ hybridization further showed that the mRNA level increased during prophase I in the male, with the strongest expression seen at the transition from mid- to late pachytema (Stage VII-VIII). Furthermore, initiation of Tesmin transcription paralleled that of the synaptonemal complex protein 1 transcript (Scp1) in the fetal ovary and prepubertal testis. We, therefore, propose that Tesmin is likely to have a function in both the male and female meiotic prophase I. Moreover, the distinct difference in both the timing and the level of mRNA accumulation in the two gender's meiotic prophase I suggests that Tesmin transcription may be controlled by two different mechanisms during male and female meiosis. Mol. Reprod. Dev. 67: 116-126, 2004.

Amino Acid Sequence↗
PubMed2004

Orthotopic autotransplantation of cryopreserved ovarian tissue to a woman cured of cancer - follicular growth, steroid production and oocyte retrieval.

Cryopreservation of human ovarian tissue is now an option for cancer patients facing treatment with gonadotoxic regimes, as a means of preserving their fertility. So far, there have been only a few reports on autotransplantation of frozen-thawed tissue with regard to restoration of ovarian function. The present report describes a 32-year-old woman diagnosed with Hodgkin's lymphoma, who had cryopreserved ovarian tissue transplanted orthotopically after secondary ovarian failure due to chemotherapy. Only 8 weeks after transplantation, ultrasonography of the remaining ovary revealed two follicles with diameters of 10 and 15 mm. Concomitantly, circulating concentrations of oestradiol increased, while concentrations of gonadotrophins decreased. In the following months, the patient menstruated three times. Subsequent pituitary down-regulation with a gonadotrophin-releasing hormone (GnRH) agonist and ovarian stimulation resulted in development of one pre-ovulatory follicle from which a metaphase II oocyte was retrieved; however, this oocyte was unable to sustain further development after intracytoplasmic sperm injection (ICSI). Intrafollicular concentrations of oestradiol and progesterone suggested a normal luteinizing response of the follicle to human chorionic gonadotrophin stimulation. A 7-month follow-up revealed continued vivid follicular activity and normal oestradiol concentrations. In conclusion, cryopreserved human ovarian tissue restored ovarian function for several cycles and sustained development of mature oocytes in a woman cured of cancer.

Adult↗
PubMed2003

Do basal oestradiol and oestradiol:androgens and oestradiol:FSH ratios reflect pregnancy potential of women receiving intrauterine insemination during natural cycles?

The aim of this retrospective study was to evaluate whether basal hormone profiles could be related to the ability to achieve pregnancy in women receiving intrauterine insemination (IUI) treatment during their natural menstrual cycle. Serum hormone profiles on cycle day 3 of naturally menstruating women were assessed in a total of 163 treatment cycles (29 conceptional and 53 non-conceptional cycles of 27 women who became pregnant and 81 non-conceptional cycles of 33 women who did not become pregnant). Basal concentrations of LH, FSH and prolactin were similar between conceptional and non-conceptional cycles. In contrast, concentrations of oestradiol in conceptional cycles (38 +/- 26 pg/ml: mean +/- SD) were significantly higher than those in non-conceptional cycles (23 +/- 18 pg/ml) (P = 0.0003). Concentrations of androstenedione and testosterone were lower but not significantly so in conceptional cycles as compared with non-conceptional cycles. The ratios of oestradiol/androstenedione, oestradiol/testosterone and oestradiol/FSH were significantly higher in conceptional as compared with non-conceptional cycles (29, 2.3, 6.2 versus 17, 1.2, 3.6 respectively) (all P < 0.006). Thus, increased concentrations of oestradiol and increased oestradiol/androgens and oestradiol/FSH ratios already on day 3 of the natural menstrual cycle correlate with the likelihood of achieving conception during the following IUI treatment. Therefore, measurement of basal hormones, including androstenedione and testosterone, may be useful to assess the health status of the coming dominant follicle.

Adult↗
PubMed2003

Number of germ cells and somatic cells in human fetal testes during the first weeks after sex differentiation.

BACKGROUND: This study presents the number of germ cells and somatic cells in human fetal testes during week 6 to week 9 post conception, i.e. the first weeks following sex differentiation of the testes. METHODS: One testis with attached mesonephros from each of 10 individual legal abortions was used. After recovery of the fetus, the testes were immediately isolated, fixed and processed for histology. The optical fractionator technique, a stereological method, was utilized to estimate the total number of germ cells in ten testes and somatic cells in six of them. RESULTS: The number of germ cells per testis increased from approximately 3000 in week 6 to approximately 30000 in week 9. The ratio of germ cells to Sertoli cells was approximately 1:11 and the ratio of germ cells to somatic cells was approximately 1:44 throughout this period. CONCLUSIONS: For the first time, germ cell and somatic cell number have been determined during early human fetal testis development. Knowledge of the number of germ cells in this period may be very important, because several environmental pollutants are suspected to result in decreased semen quality in men born of mothers exposed to these pollutants during pregnancy.

Cell Count↗
PubMed2002

Parental periconceptional smoking and male: female ratio of newborn infants.

We assessed whether the smoking habits of parents around the time of conception affects the likelihood of the offspring being male or female. We found that the offspring sex ratio (male to female) was lower when either one or both of the parents smoked more than 20 cigarettes per day compared with couples in which neither of the parents smoked. We found the lowest sex ratio among children whose mothers and fathers both smoked more than 20 cigarettes per day (p<0.0001). Parental periconceptional smoking might be a contributing factor to a lower male to female sex ratio of offspring.

Adult↗
PubMed2002

Role of meiosis activating sterols, MAS, in induced oocyte maturation.

Meiosis of follicle enclosed oocytes is maintained in the prophase of the first meiotic division and oocytes do not spontaneously resume meiosis during oocyte growth and follicle development. Arrest of the meiotic process is most likely secured by the presence of follicular purines, e.g. hypoxanthine, which maintain high levels of cAMP in the oocyte and which also in vitro prevent oocytes from resuming meiosis. Only in response to the mid-cycle surge of gonadotropins will oocytes of preovulatory follicles overcome the meiosis arresting effect of hypoxanthine and resume meiosis proceeding to the metaphase of the second meiotic division. Morphologically, resumption of meiosis is observed by the disappearance of the oocyte's nuclear membrane (germinal vesicle), a process called germinal vesicle breakdown (GVB). The molecular mechanism down-stream to receptor activation by which the mid-cycle surge of gonadotropins induces oocytes to resume meiosis is, however, only partly understood. The oocyte itself lacks gonadotropin receptors and its action is mediated through the attached cumulus cells. In vitro it has been shown that FSH induces synthesis of a signal in the cumulus cells, which overcomes the meiosis arresting effect of hypoxanthine. We have shown that a group of sterols, meiosis activating sterols (MAS), induces oocyte maturation in vitro even in oocytes depleted of cumulus cells. MAS were identified as intermediates in the cholesterol biosynthesis between lanosterol and cholesterol. The two best characterized members of the MAS family are FF-MAS purified from human follicular fluid (4,4-dimethyl-5alpha-cholest-8,14,24-triene-3beta-ol) and T-MAS purified from bull testicular tissue (4,4-dimethyl-5alpha-cholest-8,24-diene-3beta-ol). The synthesis, quantification, localization and tissue-accumulation of MAS are reviewed. Several publications have documented the pharmacological effect of MAS in different species, including oocytes from mouse, rat and human. Conflicting results obtained by the use of sterol synthesis inhibitors, which prevent MAS-accumulation, are also discussed. Whether FSH actually uses MAS as a signal transduction molecule for inducing oocyte maturation and the mechanism by which MAS induce resumption of meiosis is currently unknown, but data to support that MAS is part of the FSH induced signal transduction pathway are presented.

Animals↗
PubMed2002

Progesterone and 17 alpha-OH-progesterone in concentrations similar to that of preovulatory follicular fluid is without effect on resumption of meiosis in mouse cumulus enclosed oocytes cultured in the presence of hypoxanthine.

Some intermediates in the cholesterol biosynthesis between lanosterol and cholesterol are capable of inducing resumption of meiosis in cultured mouse oocytes without the presence of gonadotropins. The mechanism by which these so-called Meiosis Activating Sterols (MAS) activate the meiotic process is unknown, and it is uncertain whether they participate in the physiological control of resumption of meiosis. Recently, it has been shown that accumulation of MAS occurs in a liver cell line and in rat testis tissue cultured in the presence of micromolar concentrations of progesterone and 17 alpha-OH-progesterone. Such high concentrations of progesterone and 17 alpha-OH-progesterone only occur in fluid of preovulatory follicles. In connection with the mid-cycle surge of gonadotropins, this may represent one mechanism whereby follicular accumulation of MAS takes place. In the present study, the effect of 10 micro M progesterone and 10 micro M 17 alpha-OH-progesterone on resumption of meiosis was evaluated using mouse cumulus enclosed oocytes (CEO) cultured in the presence of 4mM hypoxanthine. By the end of the 24-h culture period, the frequency by which oocytes had resumed meiosis was assessed by the determination of germinal vesicle breakdown (GVBD). Neither progesterone nor 17 alpha-OH-progesterone or a combination showed any effect on GVBD. In addition, progesterone and 17 alpha-OH-progesterone in combination with a sub-optimal dose of FSH (4 IU/l) did not affect GVBD. In conclusion, accumulation of MAS to an extent that allows resumption of meiosis to occur in CEO is unlikely to be induced by progesterone and 17 alpha-OH-progesterone or a combination.

17-alpha-Hydroxyprogesterone↗
PubMed2002

Long-term cultures of testicular biopsies from boys with cryptorchidism: effect of FSH and LH on the number of germ cells.

BACKGROUND: A long-term culture system of testicular biopsies from boys with undescended testes was established to evaluate the effect of gonadotrophins on germ cell survival and growth. METHODS: Biopsies from 25 boys with cryptorchidism, aged 1.1-9.9 years, were obtained at the time of surgery. Each biopsy was subdivided into fragments and cultured for 1 or 3 weeks in a testis culture medium without gonadotrophins or supplemented with FSH (50 IU/l) or LH (5 IU/l), or a combination of FSH (50 IU/l) plus LH (5 IU/l). The survival of the germ cells was evaluated by calculating the ratio of spermatogonia and gonocytes per cross-sectioned testicular tubule, the S/T ratio. RESULTS: All cultured fragments maintained their overall morphology. A significantly reduced S/T ratio was observed in the fragments cultured in the presence of LH (P = 0.006), independently of the culture period. The mean tubular diameter in fragments cultured for 1 week with hormones was significantly larger than that of the controls (P < 0.0002). All cultured fragments had a larger tubular diameter than the uncultured fragments (P = 0.0002). CONCLUSIONS: This culture system supports survival of spermatogonia for at least 3 weeks. LH either alone or in combination with FSH results in a significantly reduced S/T ratio.

Biopsy↗
PubMedDate not supplied

Oocyte number in newborn mice after prenatal octylphenol exposure.

The aim of the present study was to investigate whether prenatal exposure to the suspected estrogenic compound 4-tert-octylphenol (OP), influences oocyte number in newborn female mice. In addition, effects on the percentage distribution of prefollicular, follicular, and atretic oocytes were investigated. Pregnant mice were subcutaneously injected with OP (1 or 250 mg/kg) or vehicle alone on embryonic day 11.5-16.5 (plug = embryonic day 0.5). As a positive control for estrogenic effects, a group of animals was injected with the synthetic estrogen diethylstilbestrol (DES, 100 microg/kg). Ovaries from the offspring were collected on the day of birth and a stereologic method, the optical fractionator, was used to estimate the number of prefollicular, follicular, and atretic oocytes in the ovaries. The total number of oocytes was calculated as the sum of the three subpopulation estimates. Neither OP nor DES exposure could be observed to affect the total number of oocytes or the percentage distribution of atretic, prefollicular, and follicular oocytes. Thus, prenatal OP exposure does not appear to cause a serious threat to fetal female germ cell proliferation and survival, or early follicle formation.

Animals↗