Single Preovulatory Follicle Research Articles

Equine chorionic gonadotropin increases estradiol levels in the bovine oviduct and drives the transcription of genes related to fertilization in superstimulated cows.

In the bovine oviduct, estradiol (E2) stimulates secretion and cell proliferation, whereas progesterone (P4) suppresses them. In this study, we have evaluated the effect of two superstimulatory protocols (follicle-stimulating hormone [FSH] or FSH combined with equine chorionic gonadotropin [eCG]) on the oviductal levels of E2 and P4 and its outcome on oviductal cells. Compared with the control group (a single pre-ovulatory follicle), we have observed that the cows submitted to FSH/eCG treatment showed a higher concentration of E2 in the oviduct tissue, together with a higher abundance of messenger RNA encoding steroid receptors (ESR1 and progesterone receptor), and genes linked to gamete interactions and regulation of polyspermy (oviduct-specific glycoprotein 1, heat-shock protein family A member 5, α-l-fucosidase 1 [FUCA1], and FUCA2) in the infundibulum and ampulla segments of the oviduct. However, we did not observe any modulation of gene expression in the isthmus segment. Even though the FSH protocol upregulated some of the genes analyzed, we may infer that the steady effect of FSH combined with eCG on oviduct regulation might benefit fertilization and may potentially increase pregnancy rates.

Abstract P4-14-13: Tamoxifen induced ovarian hyperstimulation during hormonal therapy for breast cancer

Abstract Introduction Adjuvant endocrine therapy is an integral compo-nent of care for endocrine-dependent breast cancer. To date, international consensus statements recommend tamoxifen (20 mg/day) for five years as the standard adjuvant endocrine therapy for premenopausal women. Tamoxifen is a potent inducer of ovarian function and consequent hyper-estrogenism in premenopausal women. However, the incidence rate and risk factors associated this phenomenone were not clarified. Methods Among consecutive patients who were operated under diagnosis of breast cancer from March 2012 to December 2016 in Chung-Ang university hospital, patients who received post-operative tamoxifen therapy for endocrine-dependent breast cancer (stage 0-III) at age under 60 were selected and retrospectively analysed. Serial data on serum estradiol and follicular stimulating hormone(FSH) were collected. When the serum concentration of estradiol was higher than 400 pg/mL, which exceeds the normal estradiol production by a single preovulatory follicle, we classified them as tamoxifen induced ovarian hyperstimulation group. Clinicopathologic factors were analyzed between ovarian hyperstimulation group and non-hyperstimulation group by x2 and student t-test. Results Among 205 patients, 19 patients(9.3%) showed high values of serum estradiol during tamoxifen therapy. They showed 44 times of high estradiol level during follow up period. The serum concentrations of estradiol and FSH were 1047.97638.8pg/mL and 11.57.3 mIu/mL, respectively. The mean duration from the start of the single administration of tamoxifen to the initial detection of a high concentration of estradiol was 666.4+433.1 days. Univariate and multivariate analysis between ovarian hyperstimulation and non-hyperstimulation groups showed younger age(<40years) and only endocrine therapy without chemotherapy were related to higher prevalence of ovarian hyperstimulation significantly. (p <0.001, =0.031 each) Pathologic stages and progesterone receptor expressions on breast tumor were not related to manifestation of ovarian hyperstimulation. Conclusions The Incidence rate and occurrence time of ovarian hyperstimulation associated with adjuvant tamoxifen treatment in breast cancer patients under age 60 were 9.3% and around 2-year after treatment with tamoxifen. Young age under 40 years old and endocrine treatment without chemotherapy were risk factors predicting occurrence of ovarian hyperstimulation during tamoxifen treatment. It should be noted that tamoxifen is a potent inducer of ovarian function and close monitoring of the endocrine parameters during treatment with tamoxifen would be essential. Citation Format: Kim MK, Shin H-c. Tamoxifen induced ovarian hyperstimulation during hormonal therapy for breast cancer [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P4-14-13.

Factors affecting side of ovulation in heifers and mares—A comparative study

Effect of side (left ovary, LO; right ovary, RO) and intraovarian presence of the regressing corpus luteum (CL) on the preovulatory follicle (PF) and ovulation were studied using ultrasonic- records of complete interovulatory intervals (IOI) for 500 IOI in heifers and 485 IOI in mares. Only IOI with a recording of side of a single PF and a single CL at each end of the IOI were used. In heifers, ovulation at the end of the IOI occurred more frequently (P < 0.0001) from RO (n = 285, 57%) than LO (n = 215, 43%). In mares, frequency of ovulation did not differ between RO (n = 250. 52%) and LO (n = 235, 48%). In heifers but not in mares, the number of predeviation follicles has been reported to be greater in RO than LO. In heifers, RO ovulation was more frequent when CL was in PF ovary (66%) than when CL was in opposite ovary (50%). There was no difference in side of ovulation (RO, 50%, LO, 50%). In mares, there were no significant main effects or interactions for frequency of ovulation involving side and intraovarian presence of the CL. On a species comparative basis, the present and reported results supported hypothesis 1 that a greater number of predeviation follicles in RO than in LO is associated with the predilection for RO ovulation. Results supported hypothesis 2 that ovulation in heifers is more frequent from RO than LO only when the preovulatory follicle and regressing CL are in the same ovary.

Vitrified macaque ovarian cortical tissue transplanted to heterotopic sites produces fertilizable oocytes

To determine which heterotopic transplantation sites produce competent oocytes from vitrified ovarian cortical tissue. Randomized, longitudinal, in vivo. Ovarian cortical pieces (3x6x0.5 mm3) from adult (n=4; 6-9 yrs) and peripubertal (n=4; 4-5 yrs) rhesus macaques were vitrified using glycerol:ethylene glycol containing non-permeating polymers, placed into straws and cooled in LN2 with cryoprotectants removed in sucrose [1]. Within the same animal, pieces were transplanted to subcutaneous (sc) sites [2,3] in the arm (n=4); sc abdomen (n=4); sc abdomen + omental tissue (n=2) or retroperitoneal + omentum (n=2); and bilateral mesosalpinx sites (n=2). Serum was analyzed for estradiol (E) and progesterone (P) to determine ovarian cyclicity during one year post-transplantation. When E reached at least 100 pg/ml and the preovulatory follicle was 3-6 mm diameter, hCG (1000 IU, im) was given [3]. In alternate cycles, follicles were aspirated 30 hr later. Mature oocytes were inseminated in vitro. All animals resumed cyclic ovarian cyclicity based on midcycle E rise and luteal phase P. There was no difference in the time to the first cycle post-transplantation between adult (5.9±0.8 mos) and peripubertal (6.0±0.8) animals, or the number of ovarian cycles displayed during the year (7±1 vs 6±1, respectively). The total number of preovulatory follicles seen in the sc arm (2) and sc abdomen (2) was less (P<0.01) than those seen in the sc abdomen + omentum (14), retroperitoneal + omentum (10) and mesosalpinx (11). A single preovulatory follicle typically developed at a single site within each animal during a given month despite the presence of multiple transplants. The numbers of preovulatory follicles observed and oocytes collected were similar between adults and peripubertal animals. Of 38 total follicles that developed, 31 were aspirated yielding 21 oocytes (68%); 52% metaphase II, 24% metaphase I, 24% degenerated and no immature oocytes. Three oocytes fertilized, and two cleaved to the 4-cell (from mesosalpinx) and 8-cell stage (retroperitoneal + omentum), and one developed to a morula (sc abdomen + omentum). Vitrified ovarian cortical tissue transplanted to retroperitoneal or sc abdominal sites containing omentum and in the mesosalpinx consistently developed a single preovulatory follicle and produced steroid hormones typical of normal ovarian cycles. A competent oocyte was retrieved from each of these sites and efforts to produce offspring are ongoing. Heterotopic transplantation of vitrified ovarian tissue is promising for cancer survivors seeking fertility who sustain extensive ovarian damage after cancer therapy that may preclude re-vasculariztion to support orthotopic transplantation.

Effect of multiple vs. single preovulatory follicle on oocyte quantity and quality andin vitromaturation of goat oocytes

The present study was conducted to investigate the effects of multiple vs. single preovulatory follicle on oocyte quantity and quality and in vitro maturation of goat oocytes. Slaughtered goat ovaries were collected and ranked into 2 types according to the number of preovulatory follicles on their surface: Type I (with multiple preovulatroy follicles, ≥ 2 follicles), Type II (with single preovulatory follicle). The number of goat oocytes retrieved from follicles (2–6 mm O) was recorded for each ovarian type. The released immature goat oocytes were scored for cumulus - oocyte cell adhesion into one of 3 grades (C+; cumulus - enclosed oocytes, C+/-; cumulus partially enclosed oocytes, C−; cumulus - free oocytes). Grade C+ and grade C+/ were matured in tissue culture media (TCM -199) supplemented with 10% Fetal Calf Serum for 30 h in CO2 incubator at 38.5oC and 95% humidity. The results indicated that a greater number of aspirated oocytes were found in type I than type II. The number of Grade C+ and Grade C+/- oocytes in Type I was significantly higher (P < 0.05) than type II. The in vitro maturation rate of oocytes recovered from goat ovaries was non significantly different in both types but the number of cumulus - full expanded oocytes (CE+) appeared to be higher in ovaries having multiple than single preovulatory follicle. In conclusion, higher quantity, quality and maturation rate of oocytes may produce in multiple preovulatory follicles of goat ovaries.

The 3D vascular status of the follicle after HCG administration is qualitatively rather than quantitatively associated with its reproductive competence

The objective of this study was to determine whether the vascular status of a single pre-ovulatory follicle is associated quantitatively and/or qualitatively with its reproductive competence. We studied 61 monofollicular IVF-embryo transfer cycles. Just before single oocyte retrieval, follicle vascularization was detected by transvaginal power-Doppler, 3-dimensionally reconstructed, and analysed quantitatively by coloured/gray voxel ratio [vascularization index (VI)] and qualitatively by blood cell displacement [flow index (FI)] calculation. Cycles were sorted in two sets of two groups: low VI (<or=8%, n = 44) and high VI (>8%, n = 17); low FI (<or=30, n = 22) and high FI (>30, n = 39). Patients' characteristics, fertilization rates, and embryo morphology were comparable in all groups. In contrast, clinical pregnancy rates/oocyte retrieval (4% versus 33%, P < 0.009) and implantation rates (11% versus 50%, P < 0.04) were markedly poorer in the low as compared to the high FI groups, respectively, but remained similar between the low and the high VI groups (22% versus 23% and 38% versus 44%, respectively). A qualitative (FI) rather than quantitative (VI) relationship exists between vascular status and functional quality of the follicle after HCG administration.

Follicle Selection in Primates: “Many Are Called but Few Are Chosen”1

During the follicular phase of humans and most nonhuman primates, a single preovulatory follicle usually matures each menstrual cycle. The observation that numerous preovulatory follicles may be stimulated to mature when exogenous gonadotropins are administered indicates that there must be a precise and highly reproducible mechanism by which only one of the many follicles capable of ovulating actually does so. The goal of this review is to summarize past and current research which indicates that follicle selection in primates is the result of an exquisitely sensitive interplay between gonadotropin secretion by the pituitary gland, steroid production by the ovary, and maturation-dependent alterations of the ovary's responsiveness to gonadotropins.

Modifications in gonadotropin signaling: a key to understanding cyclic ovarian function.

The enigma in understanding the regulation of ovarian function throughout the menstrual cycle is that both follicle-stimulating hormone (FSH) and luteinizing hormone (LH) act on the ovary, at least in part through the cyclic adenosine monophosphate (cAMP) intracellular signaling pathway. If cAMP is a common intracellular messenger of gonadotropic stimulation during both the follicular and the luteal phases, how can the responses of the follicle and the corpus luteum to their respective trophic hormones differ so dramatically? The actions of FSH and LH on the ovary are summarized and a mechanistic hypothesis is provided as to how ovarian cyclicity (initiation of follicular development, selection of a single preovulatory follicle, corpus luteum function, corpus luteum regression, and corpus luteum rescue during early pregnancy) could be controlled by a single intracellular messenger: cAMP.

First established pregnancy and birth after induction of ovulation with recombinant human follicle-stimulating hormone in polycystic ovary syndrome

This case report describes the first established pregnancy and birth after induction of ovulation with recombinant human follicle-stimulating hormone (FSH) in a woman suffering from chronic clomiphene-resistant anovulation due to polycystic ovary syndrome (elevated serum luteinizing hormone and testosterone concentrations together with polycystic ovaries). Starting on day 3 of a progestagen withdrawal bleeding, 75 IU of rFSH was administered i.m. daily until a single preovulatory follicle was seen upon transvaginal ultrasound examination at day 13. Ovulation was induced by a single i.m. administration of 10,000 IU of human chorionic gonadotrophin, after which a viable singleton pregnancy was revealed at a gestational age of 6 weeks. The course of pregnancy and labour was uneventful and no abnormalities were found upon a paediatric examination.

Efficacy of clomiphene citrate in the treatment of luteal phase deficiency: quantity versus quality of preovulatory follicles

We tested the hypothesis that the efficacy of clomiphene citrate (CC) in the treatment of luteal phase defect (LPD) is related more to the number of ovulatory follicles than to the quality of a single follicle. Eighteen ovulatory women with LPD as defined by endometrial biopsies that lagged behind chronological dates by at least 3 days on two separate menstrual cycles were studied. During the menstrual cycle before treatment and also during a treatment cycle (100 mg of CC, on days 5 to 9), we obtained an endometrial biopsy 9 to 12 days after ovulation. All biopsies were read in a blinded fashion by the same gynecological pathologist. During the treatment cycle, 10 women had more than one preovulatory follicle (greater than 15 mm, mean of three dimensions), while 8 had one preovulatory follicle. Luteal phase defect was corrected according to biopsy in 8 of the 10 women with more than one preovulatory follicle, but in only 2 of the 8 women with a single preovulatory follicle.

Cell-specific expression of immunoreactive cholesterol side-chain cleavage cytochrome P-450 during follicular development in the rat ovary.

Using a specific antiserum against rat cholesterol side-chain cleavage cytochrome P-450 (P-450scc), we examined the expression of this key steroidogenic enzyme during follicular development in PMSG-treated immature rats. The accumulation of the enzyme was monitored in ovary homogenates by quantitative immunodot blot assay, while expression of P-450scc in various cell types was visualized concomitantly by immunofluorescent staining of ovarian cryosections. Before PMSG treatment, no labeling of P-450scc could be observed in follicular granulosa cells. In contrast, steroidogenic cytochrome was markedly expressed in interstitial cells, part of theca interna cells, and hypertrophied theca of atretic follicles. As a result of PMSG treatment, the interstitial thecal cells promptly enriched their P-450scc content within 24 h, whereas the granulosa cells acquired the enzyme at a later time, between 30 and 48 h after hormone administration. After ovulation, many corpora lutea filled most of the ovarian volume, and the ovarian content of P-450scc was 47 times higher than that in control ovaries of untreated rats. In granulosa cell population of a single preovulatory follicle, a downward gradient of P-450scc expression was observed, starting high in the cells abutting the basal lamina and decreasing toward the cells lining the antrum. Cumulus cells failed to express P-450scc. Referring to the basal lamina, theca interna cells exhibited a reverse gradient of P-450scc expression, starting high in peripheral cells close to the theca externa layer and decreasing in cells located near the follicular basement membrane. Immunofluorescent labeling revealed a major difference between P-450scc expression in thecal cells compared to that in granulosa cells. While expression of P-450scc in granulosa cells was restricted exclusively to cells within preovulatory follicles, P-450scc labeling was observed throughout the ovary in thecal and interstitial cells associated with follicles at any phase of follicular maturation. Therefore, it may be proposed that the thecal and interstitial cells represent an all ovarian network which expresses its steroidogenic capacity at early stages of follicular maturation and thereby is able to supply androgens necessary for the follicular development.

Control of Preovulatory Follicular Estrogen Biosynthesis in the Human Ovary

Granulosa cells and follicular fluid were harvested from individual follicles at various stages of development during the midfollicular-early luteal phases of the cycle. Thirty-nine follicles between 5–28 mm diameter were studied. Granulosa cell estrogen synthetase (aromatase) activities were measured in vitro and related to corresponding follicular fluid levels of estrogen (l7βestradiol and estrone) and aromatase substrate (testosterone and androstenedione). The aromatase activity of thecal tissue from four dominant (22–28 mm in diameter) preovulatory follicles was also determined. 1) Granulosa cell aromatase activity and follicularfluid estrogen level were positively correlated (r =0.97) and were maximal in preovulatory follicles. 2) Granulosa cell aromatase activity and the follicular fluid aromatizable androgen to estrogen concentration ratio were negatively correlated (r =-0.97) and were lowest in preovulatory follicles. 3) Before the midcycle LH surge, all noncystic follicles had relatively constant follicular fluid aromatizable androgen levels, sufficient to drive the aromatase reaction rate of their granulosa cells maximally in vitro. 4) The single preovulatory follicle recovered during the LH surge had reduced follicular fluid levels of androgen and estrogen, although its granulosa cell aromatase activity remained maximalin vitro. 5) The uniformly low aromatase activity of granulosa cells recovered from nonovulatory follicles was occasionally stimulable by FSH in vitro. 6) Follicles yielding granulosa cells with a FSH responsive aromatase system were also present during the early luteal phase of the cycle. 7) In vitro, the aromatase activity of the granulosa cell layer was estimated to be at least 700 times higher than thatof the theca from estrogen secretory, preovulatory follicles. It is concluded that the activity of the granulosa cell aroma-tase system, controlled by FSH, is a critical determinant of the intrafollicular sex steroid content of developing preovulatory follicles and that the granulosamay be the main biosynthetic source of estrogen in the dominant follicle.