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A randomized, double-blind, placebo-controlled comparison of the impact of low-dose and triphasic oral contraceptives on follicular development.

OBJECTIVE: This investigation tests the hypothesis that triphasic oral contraceptives are associated with the development of large, persistent ovarian cysts. STUDY DESIGN: Weekly vaginal ultrasonography was used in a randomized, double-blind, placebo-controlled, parallel-group, single-center study that compared the incidence, risk, size, and time to resolution of ovarian follicles in healthy women who took Estrostep or Loestrin oral contraceptives (manufactured by Parke-Davis) or a placebo during three consecutive menstrual cycles. RESULTS: Sixty-three percent of placebo-treated subjects developed follicles greater than 18 mm, compared with 39% and 23% in the Estrostep and Loestrin groups. The risks for each group of developing a large follicle during a single cycle were not different. No dominant follicle persisted for greater than 2 weeks for any subject. CONCLUSION: These results demonstrate that follicular development continues during treatment with oral contraceptives. In addition, the findings fail to support the hypothesis that triphasic oral contraceptives result in persistent ovarian cysts.

Adult↗

Changes in peripheral levels of bioactive and immunoreactive inhibin, estradiol-17 beta, progesterone, luteinizing hormone, and follicle-stimulating hormone associated with follicular development in cows induced to superovulate with equine chorionic gonadotropin.

Changes in concentrations of bioactive and immunoreactive (ir-) inhibin, estradiol-17 beta, progesterone, LH, and FSH in peripheral blood were determined in cows induced to superovulate with eCG. The pattern of follicular growth was also characterized by daily ultrasonographic examination. Hormonal profiles and follicular development during the intact estrous cycle of the same animals before eCG treatment served as controls. Equine CG increased the number of follicles of various sizes (small, greater than or equal to 4 less than 7, medium, greater than or equal to 7 less than 10; large, greater than or equal to 10 mm in diameter) by 4 days after administration. The second growth of large follicles occurred within 1 day after superovulation. Inhibin bioactivity in jugular vein blood was detectable 48 h after eCG injection (44 h before LH peak), whereas it was not detected before administration of eCG or during control cycles. Circulating levels of bioactive inhibin further increased during the two waves of growth of large follicles. The highest activity of inhibin was noted at the time of the preovulatory LH peak (0 h). Thereafter, bioactivity of inhibin in peripheral plasma dropped from 0 to 24 h after the LH peak, and the activity increased again at 72 h compared to the value at -44 h. Plasma levels of ir-inhibin showed a pattern similar to changes in bioactive inhibin in the eCG-treated cows. Plasma concentrations of estradiol-17 beta also increased concomitantly with two waves of growth of large follicles. There was no correlation between plasma levels of progesterone and inhibin.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

Influence of short-term fasting during the luteal phase of the estrous cycle on ovarian follicular development during the ensuing proestrus of ewes.

Short-term fasting of mature ewes during diestrus results in increased serum concentrations of progesterone and a delayed pre-ovulatory surge release of LH. To determine if these changes in reproductive hormones influence subsequent follicular development, mature ewes observed in estrus were assigned randomly to control (n=10) or fasted (n=15) groups. Control ewes had ad libitum access to feed, whereas fasted ewes were not fed from day 7 through 11 of their estrous cycle. Daily blood samples were collected from control and fasted ewes throughout the fasting period. Fasting increased (P<0.001) serum concentrations of progesterone (4.4 ng/mL versus 2.7 ng/mL [+/-0.3]). On day 12, all ewes were treated with 10mg of PGF(2alpha) and fasted ewes were returned to ad libitum feed. Ovaries were collected from ewes (n=5 each group) at 0 and 72 h following PGF(2alpha) in control and 0, 72 and 96 h in fasted ewes. Ovaries were weighed and small (< or =2mm), medium (3-4mm), and large (> or =5mm) follicles were enumerated. Total numbers of follicles were less (P<0.001) in fasted than fed ewes (14.6 versus 30.2 [+/-2.2]) at 0 h, but did not differ (P=0.9) when numbers of follicles were compared at similar times before the anticipated LH surge (i.e., at 72 h versus 96 h in control and fasted ewes, respectively). Within follicular size class, numbers of small and medium follicles were decreased (P=0.04) at 0 h in fasted ewes. Numbers of large follicles did not differ (P=1.0) between groups. Although numbers of small and medium ovarian follicles in fasted ewes recovered by 96 h to values comparable to fed ewes at 72 h following PGF(2alpha), serum concentrations of estradiol 17beta (P=0.08) and FSH (P=0.06) tended to be decreased in fasted ewes before the anticipated surge release of LH. Pituitary content of LH and FSH also tended to be lower (P< or =0.09) at 96 h in fasted ewes than at 72 h in control ewes, but did not differ (P> or =0.4) at hour 0 following PGF(2alpha). Hypothalamic and stalk median eminence contents of GnRH were not influenced (P> or =0.2) by fasting at any time period. Fasting during the luteal phase perturbs gonadotropin secretion and may influence fertility by causing a delay in ovarian follicle development.

Animals↗

Ovarian H3K27ac remodeling is associated with impaired follicular development in laying hens with fatty liver hemorrhagic syndrome.

Fatty liver hemorrhagic syndrome (FLHS) is a metabolic disease of laying hens that reduces egg production and is accompanied by reproductive impairment, but the ovarian regulatory mechanisms that connect nutritional stress to follicular dysfunction remain unclear. This study examined whether active chromatin remodeling in the ovary is associated with FLHS induced by a high-energy, low-protein (HELP) diet. Hy-Line Brown hens were assigned to a basal diet or HELP diet, and ovarian tissue was collected for histone H3 lysine 27 acetylation (H3K27ac) chromatin immunoprecipitation sequencing and RNA sequencing. The HELP diet reduced laying performance and the numbers of small yellow and hierarchical follicles, indicating compromised follicular development. Genome-wide H3K27ac profiling identified 2,111 regions with lower acetylation and 1,707 regions with higher acetylation in FLHS ovaries. Genes linked to differential H3K27ac regions were enriched in pathways related to oocyte meiosis, cell cycle control, FoxO signaling, gonadotropin-releasing hormone signaling, and steroid hormone biosynthesis. RNA sequencing identified 341 differentially expressed genes, with a predominance of downregulated genes. Integration of chromatin and transcriptome data highlighted folliculogenesis-related genes, including FGF1, FGF9, and MMP10, that showed reduced H3K27ac enrichment together with decreased expression. Super-enhancer analysis further identified 131 regions with reduced H3K27ac signal in FLHS ovaries, including regions located near PCNA and RAP1A, two genes involved in cellular proliferation and survival signaling. Motif enrichment of differential H3K27ac regions implicated Fos, SF-1/NR5A1, and GATA-4 as candidate transcriptional regulators. These findings indicate that HELP diet-induced FLHS is associated with broad attenuation of active ovarian regulatory elements and reduced expression of genes required for follicle growth, tissue remodeling, and steroidogenic function. The study provides an ovarian epigenomic framework for understanding reproductive decline in FLHS-affected laying hens.

Fatty liver hemorrhagic syndrome↗

Effect of melengestrol acetate (MGA) or progesterone-releasing intravaginal device (PRID) on follicular development, concentrations of estradiol-17 beta and progesterone, and luteinizing hormone release during an artificially lengthened bovine estrous cycle.

Two trials were conducted to determine whether 7-d progestogen treatment beginning on d 17 of the estrous cycle altered 1) ovarian follicular development, 2) serum concentration of estradiol-17 beta (E2) and progesterone (P4), and 3) patterns of release of luteinizing hormone (LH). In both trials, Angus, Angus x Holstein, or Holstein cows 2 to 6 yr of age were randomly assigned to receive either melengestrol acetate (MGA, .5 mg.animal-1.d-1; n = 23), a progesterone-releaseing intravaginal device (PRID, n = 26) or to serve as untreated Controls (n = 14). Ultrasonography and blood sampling were performed daily throughout the experiment beginning on d 3 (Trial 1) or d 9 (Trial 2) of the estrous cycle. In Trial 2, blood samples were collected every 15-min for 6 h on d 17 (all cows) and d 20 and 23 (MGA and PRID cows) for determination of LH. Estrous cycle length was 3 to 5 d greater (P < .05) for MGA- and PRID-treated cows characterized by two (MGA-2 and PRID-2) or three (MGA-3 and PRID-3) dominant follicles than for control cows exhibiting two (Control-2) or three (Control-3) dominant follicles. A greater proportion (P < .05) of MGA- than of PRID-treated cows ovulated the follicle that was dominant at the beginning of treatment on d 17 (10 of 23 vs 1 of 26). Serum P4 concentrations declined 3 d earlier in Control-2 and MGA-2 cows than in Control-3, MGA-3 or PRID-3 cows.(ABSTRACT TRUNCATED AT 250 WORDS)

Administration, Intravaginal↗

Extracellular matrix in ovarian follicular development and disease.

The ovarian follicle contains several different cell types and separate compartments and undergoes substantial development during its growth and maturation. Extracellular matrix (ECM) could be expected to play a major role in these processes. Most research on ECM in follicles has focused on the follicular basal lamina and its changing composition during folliculogenesis and on the specialised matrix formed at ovulation by the cumulus cells surrounding the oocyte and the zona pellucida. We review these aspects. Few naturally occurring gene mutations have identified unique roles for ECM molecules in follicular function. Presumably, any mutations leading to reduced fertility are eliminated quickly by natural selection and, when mutations are not eliminated, considerable redundancy occurs to ensure successful reproduction. In mice, in which the genome can be easily manipulated, the modification of matrix components associated with cumulus and oocytes has often resulted in partial infertility, suggesting redundancy. We provide an update of basal lamina components focusing on newer discoveries. In addition, we review matrix associated with the occyte and cumulus cells (excluding the zona pellucida) and other components of ECM. Where possible, we examine evidence for the role of the ECM in follicular development and diseases.

Animals↗

Comparison of three methods of acute administration of progesterone on ovarian follicular development and the timing and synchrony of ovulation in Bos indicus heifers.

The aim of this study was to induce the formation of a persistent dominant ovarian follicle and to compare the effects of 3 methods of acute administration of P4 on ovarian follicular development and on the timing and synchrony of ovulation. Stage of the estrous cycle was initially synchronized in Bos indicus heifers with a norgestomet implants (3 mg) for 10 d and with an analogue of PGF2 alpha (15 mg) on the first and last day of norgestomet treatment. Eight days after removal of the implants, heifers were randomly assigned to 4 groups. All heifers received a norgestomet implant (Day 0), which was removed 17 d later (Day 17); PGF2 alpha was administered on Days 0 and 4. Heifers in the control group (n = 5) received no other treatment. On Day 10 heifers in Group P4C (n = 5) were treated with a CIDR for 24 h; heifers in Group P4O (n = 5) were administered 100 mg i.m. of P4 in oil, while heifers in Group P4S (n = 5) were administered 100 mg i.m. of P4 in saline/alcohol. Data were analyzed using bootstrap estimates of location (mean) and spread (standard deviation; SD). Compared with the control heifers, day of emergence of the ovulatory follicle was delayed, and age and duration of dominance of the ovulatory follicle were reduced in the P4C and P4O heifers (P < 0.05) but not in the P4S heifers (P > 0.05). In all groups treated with P4 both the mean and variability (SD) in the timing of ovulation did not differ with that of the control group (P > 0.05) but there was less variability in the day of emergence, age, duration of dominance and diameter of the ovulatory follicle than in the control group (P < 0.05). Delayed timing and reduced synchrony (SD) of ovulation and greater age of the ovulatory follicle (P < 0.05) occurred in P4S heifers than in P4C heifers. We conclude that administration of 100 mg of P4 in oil is as effective as treatment with a CIDR for synchronizing emergence and ovulation of a newly recruited dominant follicle. However, reduced synchrony of ovulation, greater age of the ovulatory follicle and delayed timing of ovulation occurred following administration 100 mg of P4 in saline/alcohol compared with the CIDR device.

Administration, Intravaginal↗

Avian granulosa cell prostaglandin secretion is regulated by transforming growth factor alpha and beta and does not control plasminogen activator activity during follicular development.

The aim of the present study was to determine the role of transforming factor alpha (TGF alpha) and beta (TGF beta) in the regulation of prostaglandin (PG) secretion, and the relationships between PG and plasminogen activator (PA) activity in hen granulosa cells during ovarian follicular development. Cells from the first (F1), third (F3), and fifth and sixth (F5-6) largest preovulatory follicles were cultured for up to 21 h in the presence of TGF alpha (0.1-10 ng/ml) and/or TGF beta (4-20 ng/ml) or TGF alpha together with a cyclooxygenase inhibitor, indomethacin (0.05-0.5 microM). The release of PG into the incubation medium was determined by RIA. Cell-associated (PAc) and secreted (PAs) PA activities were measured by a fibrinolysis assay and characterized by zymography. Basal PGF secretion from F1, F3, and F5-6 cells was 2.2 +/- 0.3, 2.2 +/- 0.5, and 1.1 +/- 0.3 ng/micrograms DNA, respectively, and was higher than that of PGE. Basal total PA (PAc+PAs) activity from F1, F3, and F5-6 cells was 41 +/- 13,261 +/- 68, and 958 +/- 268 x 10(3) cpm/micrograms DNA, respectively. TGF alpha stimulated PG secretion and PA activity in a dose-dependent manner. The TGF alpha-induced PA activity was predominantly associated with a molecular mass of 30-35 kDa, corresponding to that of urokinase PA. The stimulation of PG secretion by TGF alpha was maximal in F3 and F1 granulosa cells whereas PA activity in the presence of TGF alpha was highest in cells from F5-6 follicles.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

Follicular development and ovarian hormone secretion following passive immunization of ewes against inhibin or oestradiol.

Immunization against inhibin or oestradiol causes an increase in the peripheral plasma concentration of FSH. In this study we have investigated the effect of this post-immunization rise in FSH concentration on follicular development by means of real-time ultrasonography, in ewes in which an ovary and its vascular pedicle had been autotransplanted to a site in the neck. Groups of ewes on day 10 of the luteal phase of the oestrous cycle were injected with a single 10 ml i.v. bolus of plasma from normal ewes (control; n = 4), antiserum to the 1-26 peptide fragment of the N-terminus of the alpha chain of porcine inhibin (n = 5) or antiserum to oestradiol-17 beta (n = 4). The plasma concentration of FSH was unaffected by treatment in the control group but showed a significant (P < 0.001) rise following treatment in both immunized groups (inhibin-immunized 175% over 19h; oestradiol-immunized 138% over 22 h as a per cent of the original value). This rise in FSH concentration was accompanied by a significant (P < 0.001) rise in the total number of follicles > 2.0 mm per ovary in both immunized groups (inhibin-immunized 5.5 +/- 1.0 to 13.6 +/- 1.4; oestradiol-immunized 4.6 +/- 0.5 to 11.5 +/- 1.0).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

Ovarian follicular development in prepubertal heifers is influenced by level of dietary energy intake.

Objectives were twofold: 1) to determine the chronology of development of dominant ovarian follicles during the peripubertal period in heifers and 2) to determine whether feeding a diet with low energy content that delays onset of puberty alters chronology of dominant ovarian follicular development in peripubertal heifers. Ten heifers of composite breeding (1/4 Angus, 1/4 Hereford, 1/4 Red Poll, 1/4 Pinzgauer) were randomly assigned, at 8 mo of age, to receive a diet designed to produce 0.9 (n = 5) or 0.3 (n = 5) kg body weight gain per day for the duration of the experiment. To characterize changes in size of ovarian follicles, real-time linear ultrasonography of ovaries was conducted in all heifers every other day until puberty occurred. Blood samples were collected weekly to determine concentrations of progesterone and 17 beta-estradiol. Determination of time of puberty was based on increased concentrations of progesterone, ultrasound depiction of ovulation, and subsequent presence of a corpus luteum. Size of the dominant ovarian follicles differed prior to puberty (p < 0.03); diameter of the dominant ovarian follicle was greater in all heifers as the first ovulation approached as compared to earlier in prepuberty. Heifers fed the greater amount of energy exhibited larger dominant ovarian follicles at a younger age in comparison to heifers fed the lower amount of energy.(ABSTRACT TRUNCATED AT 250 WORDS)

Aging↗

Involvement of ovarian factors magnified by pharmacological induction of multiple follicular development (MFD) in the increase in Ca125 occurring during the luteal phase and the first 12 weeks of induced pregnancies.

OBJECTIVE: To evaluate the relationship of ovarian activity on Ca125 production, we studied whether Ca125 production varies during the menstrual cycle both in normal ovulatory women and in women whose ovarian factors are significantly stimulated by multiple follicular development (MFD). Furthermore, since the first 12 weeks of pregnancy is characterized by the enhancement of corpus luteum function mainly in MFD-induced pregnancies, Ca125 levels were also evaluated in the first quarter of pregnancy both in spontaneous and in MFD-induced pregnancies. SUBJECTS: Subjects were normal ovulatory women in the late follicular phase (FP) (N = 20) and in the luteal phase (LP) (N = 20), 32 infertile women submitted to MFD with pure FSH, and 40 pregnant women in which pregnancy occurred spontaneously (N = 20) or after induction of MFD (N = 20). RESULTS AND CONCLUSIONS: In regularly cycling women plasma Ca125 levels were constant during the menstrual cycle. In contrast, in stimulated cycles Ca125 levels were significantly higher (P < 0.0008) in the LP than in the FP. In addition, in these subjects Ca125 levels in the LP were significantly correlated (P < 0.0001, r = 0.686) with E2 plasma levels. These data strongly suggest that an increase in corpus luteum function could be involved in Ca125 production. Since granulosa cells have not been demonstrated to produce Ca125, it can be hypothesized that endometrial or peritoneal cells submitted to exaggerated stimulation by ovarian activity are the source of increased Ca125 secretion. In agreement with this hypothesis, Ca125 levels were significantly higher in the first weeks of spontaneous pregnancies than in the luteal phase and they were also higher in MFD-induced pregnancies than in spontaneous pregnancies (P < 0.001).

Biomarkers↗

Cellular localization of müllerian inhibiting substance messenger ribonucleic acid during human ovarian follicular development.

Müllerian inhibiting substance is expressed in the human reproductive system and has been associated with oocyte meiotic arrest. In situ hybridization was used to selectively localize ovarian cells containing high levels of müllerian inhibiting substance messenger ribonucleic acid, a müllerian inhibiting substance precursor, during different stages of human follicular development. Müllerian inhibiting substance transcript was noted in the granulosa cells of primordial, primary, and antral follicles. Surprisingly, transcript was also identified within the cytoplasm of oocytes and throughout the ovarian stroma. Controls included sense oligoprobe, positive and negative tissue controls, and treatments minus the detection antibody. Localization of transcript within the cytoplasm demonstrates that active transcription of müllerian inhibiting substance messenger ribonucleic acid occurs within both fetal and adult human female gonads. The presence of müllerian inhibiting substance messenger ribonucleic acid within oocyte cytoplasm could implicate an autocrine role for müllerian inhibiting substance-derived peptides in the establishment of oocyte competence.

Adult↗

The effects of equine somatotropin (eST) on follicular development and circulating plasma hormone profiles in cyclic mares treated during different stages of the estrous cycle.

The effects of exogenous equine somatotropin (eST) administration on ovarian activity and plasma hormone levels were evaluated on horse and pony mares. The objectives of this study were to determine the effects of eST on follicular development and circulating concentrations of leutinizing hormone (LH), estradiol, progesterone, and insulin-like growth factor I (IGF-I) in cyclic horse and pony mares. Sixteen mares received daily injections (i.m.) of eST at a concentration of 25 micrograms/kg body weight on either Days 6 through 12 (Treatment A) or 13 through 19 (Treatment B) postovulation. In addition, contemporary mares were similarly given the carrier vehicle and served as controls (Treatments C and D). Blood samples were collected at 24-hr intervals and ultrasonographic evaluations were performed on the ovaries of each mare at 48-hr intervals beginning on the first day of treatment and ending either on the day of ovulation or 5 d postovulation. Circulating levels of insulin-like growth factor-I (IGF-I) were increased in treated mares by Day 3 post-treatment (P < 0.05). Also, mares in Treatment B exhibited a decrease in plasma estradiol concentrations (P < 0.05) when compared with control mares on Days 1 through 5 postovulation of the post-treated estrous cycle. In addition, circulating leutinizing hormone levels were different for mares in Treatment A compared with controls on Days--8 through--1 pre-ovulation (P < 0.05). All follicles present on the ovaries of each mare were measured and placed into one of five categories based on their diameter. Neither the mean number of follicles per size category > or = 8 mm in diameter nor the mean follicular diameter within each size category differed among treatment and control mares. However, eST treatment significantly increased the number of follicles < or = 7 mm on the ovaries of mares treated early in the estrous cycle when compared with control mares on Days 3 and 7 post-treatment and at the onset of standing estrus.

Animals↗

Identification of follicles with fertilizable oocytes by sequential ultrasound measurements during follicular development.

Patients undergoing ovulation induction for in vitro fertilization and embryo transfer (IVF-ET) were monitored daily with serum estradiol-17 beta (E2) and ultrasound. The location of each individual follicle was established by taking ultrasound images through serial sections of the ovary. The diameter of each follicle and the volume of its follicular wall (FW) were determined from ultrasound images using a computer-controlled image analyzer. A total of 44 follicles from nine patients was studied, with an overall fertilization rate of 46% In all patients, serum E2 levels increased prior to human chorionic gonadotropin (hCG). Whereas changes in either the average diameter or the volume of the entire follicle did not identify follicles with fertilizable oocytes, FW volume measurements were predictive. Prior to hCG, FW volume increased 24 +/- 8%/day in follicles with fertilizable oocytes but decreased 3 +/- 6%/day in follicles with nonfertilizable oocytes (P less than 0.05). Three major patterns of follicular development were observed for follicles with nonfertilizable oocytes: slow growing (less than 20% increase in FW volume), nongrowing (no change in the FW volume), and "degenerating" (a decrease in the FW volume), suggesting that these follicles are "postmature." These data demonstrate that FW volume measurements made from sequential ultrasound images provide an accurate method to identify those follicles that contain fertilizable oocytes.

Chorionic Gonadotropin↗

Delayed follicular development and ovulation following inhibition of FSH with equine follicular fluid in the mare.

In two experiments, PGF(2alpha) was given to all mares on Day 10 (ovulation = Day 0). In experiment 1, mares received either whole follicular fluid or saline i.v. every 12 hours on Days 10 to 14. Experiment 2 was similar to experiment 1, except the follicular fluid was extracted with charcoal to remove steroids. Analysis of the FSH data for Days 10 to 21 indicated an effect of treatment (P<0.08) with whole follicular fluid, but not with charcoal-extracted follicular fluid. However, there was an effect of day (P<0.05) and an interaction (P<0.01) of treatment with day for both experiments. The interaction of treatment with day seemed primarily due to a marked post-treatment increase in FSH concentrations between Days 15 and 17 for mares treated with either whole follicular fluid or charcoal-extracted follicular fluid. Analysis of the diameter of the largest follicle for Days 10 to 18 indicated a main effect of treatment (P<0.05) and day (P<0.05) and an interaction (P<0.05) of treatment with day for both experiments. The interaction of treatment with day was attributable to the inhibition of follicular growth by Day 14 for mares treated with whole follicular fluid and by Day 15 for mares treated with charcoal-extracted follicular fluid. The length of the interovulatory interval was longer (P<0.05) in the treated group than in controls for both experiments. Results indicated that equine follicular fluid contained a proteinaceous substance that suppressed circulating concentration of FSH. The inhibited follicular growth and the delay in ovulation were attributed to the reduced concentrations of circulating FSH.

Journal Article↗

Per-follicle measurements indicate that anti-müllerian hormone secretion is modulated by the extent of follicular development and luteinization and may reflect qualitatively the ovarian follicular status.

OBJECTIVE: To investigate the possible influence of follicular maturation and luteinization on anti-müllerian hormone (AMH) secretion and the relationship between per-follicle AMH levels, ovarian follicular status, and responsiveness to controlled ovarian hyperstimulation (COH). DESIGN: Prospective study. SETTING: University hospital in France. PATIENT(S): Thirty seven in vitro fertilization/embryo transfer candidates undergoing COH. INTERVENTION(S): On the day of oocyte retrieval, serum samples and follicular fluids from two small (8-12 mm in diameter) and two large (16-20 mm in diameter) follicles were collected for AMH, E2, and progesterone (P4) measurements. MAIN OUTCOME MEASURE(S): Per-follicle AMH levels. RESULT(S): Small follicles secreted AMH levels that were approximately three times as high as large follicles. Follicular fluid AMH and P4 levels were negatively correlated to each other both in small and large follicles. Per-follicle AMH levels in both follicular classes were positively correlated with antral follicle count on cycle day 3 before COH and with growing follicle (> or =12 mm) count and oocytes retrieved, but negatively correlated with FSH requirement. CONCLUSION(S): Both final follicular maturation and luteinization interfere with granulosa cell AMH production. The relationship between intrafollicular AMH content, the surrounding follicular status, and ovarian response to COH indicates that peripheral AMH levels reflect not only follicle count but also per-follicle AMH production.

Adult↗

Expression profiles and chromosomal localization of genes controlling meiosis and follicular development in the sheep ovary.

In female sheep fetuses, two of the most crucial stages of ovarian development are prophase of meiosis I and follicle formation. In the present study, sheep ovaries collected on Days 25, 38, 49, 56, 67, 75, 94, and 120 of gestation, at birth, and in adulthood were tested by reverse transcription-polymerase chain reaction (RT-PCR) for the expression of 14 genes known to be involved in the ovarian differentiation in diverse organisms. The aim of this study was to determine 1) the expression pattern of six genes involved in germ cell development or meiosis (DMC1, SPO11, MSH4, MSH5, DAZL, and Boule) and five ovary-derived factors (OVOL1, SIAH2, DIAPH2, FOXL2, and FGF9), 2) the onset of gene expression for several members of the bone morphogenetic protein (BMP) pathway involved in follicular development (GDF9, BMP15, BMPR-IB), and 3) the chromosomal localization of seven of these genes in the sheep genome. The RT-PCR analysis revealed that the two germline-specific genes, DAZL and Boule, were expressed between 49 and 94 days postcoitum (dpc) with a similar pattern to typical meiosis genes (DMC1, MSH4, and MSH5), suggesting their possible participation in prophase of meiosis I. GDF9 and OVOL1 gene transcription started at 56 dpc and extended until birth, while BMP15 presented a more restricted window of expression between 94 dpc and birth, corresponding to the formation of first growing follicles. The homologous ovine genes for SPO11, DMC1, MSH5, DAZL, FGF9, DIAPH2, and SIAH2 were located on OAR 13q21-22, 3q35, 20q22, 19q13, 10q15, Xq44, and 1q41-42, respectively. In sheep, quantitative trait loci affecting female reproductive capacities are currently being detected. The ontology and precise mapping of ovarian genes will be useful to identify potential candidate genes that might underlie these effects.

Animals↗