SEARCH · Search PubMed

Results for “Follicular development”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

SourceResearch connectionFrom yearThrough year

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 379 records · Page 21Linked to original sources

PubMed1999

Evidence for a role of the alternatively spliced ED-I sequence of fibronectin during ovarian follicular development.

This study was aimed at testing the hypothesis that different forms of fibronectin (FN), produced as a consequence of the alternative splicing of the precursor messenger RNA, play specific roles during development of the ovarian follicle. In particular, we were interested in determining the effect of the ED-I (also termed ED-A) type III repeat, which is absent in the plasma form. Analysis of FN levels in follicular fluids corresponding to different stages of development of bovine follicles revealed marked changes in the concentrations of ED-I+ FN, whereas total FN levels remained relatively constant. ED-I+ FN levels were higher in small follicles, corresponding to the phase of granulosa cell proliferation. The hypothesis of a physiological role for ED-I+ FN was further supported by the finding of a regulation of the alternative splicing of FN in primary cultures of bovine granulosa cells by factors known to control ovarian follicular development. cAMP produced a 10-fold decrease in the relative proportion of the ED-I region. In contrast, transforming growth factor-beta elicited a 2-fold stimulation of overall FN synthesis and a 4-fold increase in the synthesis of ED-I containing FN. This effect was evident at the protein (Western blots) and messenger RNA (Northern blots) levels. Although a negative correlation (P < 0.001) was detected between ED-I+ FN and estradiol levels in follicular fluid, this steroid was unable to modulate in vitro the alternative splicing of FN. A possible mitogenic effect of ED-I+ FN was suggested by the observation that a recombinant peptide corresponding to the ED-I domain stimulated DNA synthesis in a bovine granulosa cell line (BGC-1), whereas a peptide corresponding to the flanking type III sequences had no effect. The hypothesis of ED-I+ FN as a growth regulatory factor was further strengthened by the fact that depletion of FN from BGC-1-conditioned medium, which contained ED-I+ FN, abrogated its mitogenic activity, whereas plasma FN was without effect. We propose that changes in the primary structure of FN may mediate some of the effects of gonadotropin and intraovarian factors during follicular development.

Alternative Splicing↗

PubMed1992

Changes in linoleic acid during follicular development and inhibition of spontaneous breakdown of germinal vesicles in cumulus-free bovine oocytes.

The fatty-acid composition of follicular fluid from small and large developing follicles was analysed and the effects of saturated and unsaturated fatty acids on spontaneous breakdown of germinal vesicles were investigated. Fatty acids were bound to bovine serum albumin and cultured with oocytes at 100 mumol/l. Linoleic acid (18:2) was the only fatty acid tested that significantly inhibited breakdown of germinal vesicles (P less than 0.01). The effect was dose-dependent and was greatest at 50 mumol fatty acid/l (% breakdown of control, 81.1 +/- 6.8 vs. 50 mumol linoleic acid/l, 35.4 +/- 7.3; P less than 0.02). Linoleic acid was the major fatty acid, constituting about a third of the total fatty acid in the follicular fluid; followed by 18.9 +/- 1.0% and 16.9 +/- 1.3% oleic acid (18:1) in small and large follicles, respectively. Saturated fatty acids accounted for less than 30% of the total fatty acid composition. There was a marked absence of tetraenoic acids in small and large follicles. Proportions of linoleic acid were significantly lower in follicular fluid from large follicles (31.1 +/- 1.2% of total fatty acid) than from small follicles (34.8 +/- 0.7% of total fatty acid) (P less than 0.05) and there was a significant inverse correlation between follicle diameter and percentage of linoleic acid in the follicular fluid (r = -0.6966; P less than 0.05). There was no significant alteration in any other fatty acid during follicular development.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1992

Relationships among concentrations of steroids, inhibin, insulin-like growth factor-1 (IGF-1), and IGF-binding proteins during follicular development in weaned sows.

The experimental objective was to determine how insulin-like growth factor binding proteins (IGFBP), as examined by Western ligand blot procedures, related to porcine follicular steroidogenesis. Weaned sows were ovariectomized at various times after litter removal in three experiments. In experiments 1 and 2, sows were ovariectomized at 48-120 h after weaning. In experiment 1, pools of all small (1-3 mm), medium (greater than 3-6 mm), or large (greater than 6-9 mm) follicles were made for each sow; in experiment 2, fluid was collected individually from the 10 largest follicles per ovary. A third experiment was conducted to examine changes after an ovulatory dose of hCG, but prior to ovulation. In this experiment, sows were treated with eCG at weaning, given hCG 72 h later, and ovariectomized 0-36 h after the ovulatory dose of hCG. Follicular fluid was collected from the 10 largest follicles per sow. In experiments 1 and 2, IGFBP-3 in follicular fluid remained constant over follicle diameters and stage sof development, and IGFBP-2 decreased with advancing follicular development as concentrations of estradiol, androstenedione, and progesterone increased. In experiment 1, after the presumed LH surge when the concentration of all steroids was low, there was a sharp increase in band intensity for IGFBP-2. Similarly, estradiol and androstenedione were low in preovulatory sows in experiment 2, though progesterone increased and IGFBP-2 decreased with follicle diameter. In experiment 3, progesterone remained elevated from 0 to 36 h after hCG, even though IGFBP-2 did not increase until after 24 h post-hCG.(ABSTRACT TRUNCATED AT 250 WORDS)

Androstenedione↗

PubMed1990

Biochemical and biophysical indices of follicular development in spontaneous and stimulated ovulatory cycles.

This study was designed to evaluate the correlation between the follicular biophysical and biochemical indicators in spontaneous (N = 11) and stimulated (N = 110) ovulatory cycles. Ovulation was induced with clomiphene citrate in 14 cycles, gonadotropin-releasing hormone (GnRH) in 12 cycles, and human menopausal gonadotropins in 84 cycles. Patients were studied daily, starting on day 10, until sonographic verification of ovulation. Each woman had serum estradiol (E2) and LH measured daily and progesterone measured only 7 days after ovulation. In addition, the ovaries were imaged transvaginally daily and the two largest follicular diameters, volumes, cross-sectional areas, and circumferences were measured in all follicles 10 mm or larger in diameter. Ultrasonographic measurements of follicles from clomiphene-stimulated cycles were significantly larger than those from spontaneous, GnRH-, and human menopausal gonadotropins-stimulated cycles (P less than .05). Serum E2 and progesterone secretion in human menopausal gonadotropins- and clomiphene-stimulated cycles were significantly higher than in spontaneous and GnRH-stimulated cycles (P less than .01). Women treated with human menopausal gonadotropins developed significantly more follicles than with any other treatment (P less than .05). Correlation analysis indicated that biophysical variables alone (follicular diameter, volume, cross-sectional area, or circumference) were good indicators of normal follicular development and predicted the mid-cycle LH surge in spontaneous (r = 0.81, P less than .001), GnRH- (r = 0.78, P less than .001), and clomiphene citrate-stimulated cycles (r = 0.83, P less than .001). However, in human menopausal gonadotropins-stimulated cycles, both serum E2 levels and ultrasonographic evaluation were necessary to decide the best time for hCG administration (r = 0.55, P less than .001).

Clomiphene↗

PubMed1990

[Follicular development during menstrual cycle and the levels of steroid hormones in the follicular fluid of women with infertility of inflammatory origin].

Gonadal hormone levels have been evaluated in the follicular fluid of 67 women with tubal and peritoneal infertility. Follicular fluid concentrations of estradiol, progesterone and testosterone were compared with sonographically ascertained follicle sizes and growth rates. The results indicate a high incidence of peripheral damage of the hypothalamic-pituitary-ovarian axis in women with inflammatory diseases of the internal genitalia.

Adult↗

PubMed1997

Control of follicular development and ovulation rate in pigs.

There is considerable evidence that nutritional and metabolic control of follicular growth is mediated by metabolic hormones and growth factors, particularly with processes mediated by insulin-like growth factor I (IGF-I) and its binding proteins (IGFBPs). From knowledge that hormones and growth factors which can be affected by diet also positively affect ovarian function, the concept has emerged that metabolic modifiers of gonadotrophin action, rather than gonadotrophins themselves, could affect follicle development. While ovulation rate can be enhanced under certain conditions in cyclic gilts, assessing influences of metabolic modifiers on the post-lactational sow is confounded by variability in the return to oestrus after weaning. In a series of studies involving insulin administration between weaning and oestrus, successive experiments produced different results, but several measures of reproductive performance were enhanced. Administration of somatotrophin (ST) has also been shown to increase follicular development in both gilts and sows. Both insulin and ST increase IGF-I production by pig ovarian follicles, and insulin is more effective than IGF-I in reducing atresia and increasing progesterone in cultured pig follicles. Whether increases in litter size are achieved after an increase in ovulation rate involves many factors, including the quality of ova and whether the increase in ovulation rate exceeds the uterine capacity to maintain pregnancy. Given the variation in genetics and management practices, development of treatments to enhance follicle quality leading to maximal litter size is challenging.

Animal Nutritional Physiological Phenomena↗

PubMed1983

Seasonal effects on ovarian follicular development in pony mares.

To define ovarian follicular kinetics in the equine ovary during anestrus and the breeding season, the follicular population of pony mares was investigated at mid-anestrus and at the beginning and end of the breeding season. There was a clear effect of season on the exit of reserve (primordial and initiated) follicles since at the beginning of the breeding season we noticed a higher mitotic index for the smaller preantral follicles, leading to an accumulation of small and medium antral follicles. In contrast, the ovaries sampled during anestrus or at the end of the breeding season were very similar; only preovulatory development was lacking in anestrous ovaries. However, atresia was unaffected by season.

Anestrus↗

PubMed1999

Expression of gap junctional proteins connexin 43, 32, and 26 throughout follicular development and atresia in cows.

Detection of connexin (Cx) proteins has been used as an indicator of the presence of structural and functional gap junctions in tissues. To examine the role of gap junctions during follicular growth and atresia, the presence of three major connexins, Cx43, Cx32, and Cx26, was evaluated in bovine ovaries by using immunohistochemistry and Western immunoblot analysis. Cx43 was not present in primordial follicles, but was present in granulosa cells of primary/secondary and antral follicles. Cx43 also was present on the borders between granulosa cells and the oocyte. Expression of Cx43 increased in healthy developing antral follicles, but decreased during follicular atresia. Cx32 was not present in healthy follicles but was present in granulosa cells of atretic antral, and especially small antral follicles. Cx26 was present in the oocyte of primordial and primary/secondary follicles, and in the granulosa and/or thecal cell layers of healthy antral follicles. The percentage of healthy antral follicles that expressed Cx26 also increased during follicular development, but decreased during atresia. Cx32 and Cx26 also were detected in ovarian blood vessels and in stromal tissues adjacent to the tunica albuginea in some ovaries. The pattern of expression of these Cx indicates that gap junctional proteins may be involved in the control of follicular growth and atresia in cows.

Animals↗

PubMed1992

Insulin-like growth factor-I (IGF-I) may not be essential for ovarian follicular development: evidence from IGF-I deficiency.

Insulin-like growth factor-I (IGF-I) stimulates growth and differentiation in follicular granulosa cells (GC). To examine whether this effect is prerequisite to human folliculogenesis, a patient with Laron-type dwarfism (IGF-I deficiency secondary to GH receptor abnormality) was examined while undergoing in vitro fertilization treatment. Despite low levels of IGF-I in serum and follicular fluid (less than 3 and less than 2 nmol/L) and very high levels of IGF-I-binding protein, the patient developed normal ovarian follicles. After the administration of GnRH analog (GnRHa) and human menopausal gonadotropin in a dose similar to that used in normovulatory women, estradiol (E2) levels reached above 5000 pmol/L on the day of hCG administration, and mature fertilizable oocytes were retrieved during ovum pickup. The patient's GC E2 production, tested in a primary culture, did not respond to IGF-I after 4 days of incubation, while control cultures showed a significant increase. Only after a priming period of 7 days did IGF-I have a significant effect on E2 production, as observed in the patient's GC culture. This delayed response suggests that the patient's GC were not exposed in vivo to IGF-I. Our data support the view that IGF-I is not required for normal follicular development, but is, rather, a nonessential modulator of FSH action.

Adult↗

PubMed1993

Immunohistochemical localization of 3 beta-hydroxysteroid dehydrogenase in the rat ovary during follicular development and atresia.

In the adult ovary, cohorts of growing follicles are continuously generated, from which dominant follicles are selected during each estrous cycle. To compensate for the rapid proliferation of follicular cells in the growing pool of follicles, follicles are eliminated by atresia, thereby maintaining ovarian tissue mass. Estrogens and androgens have been implicated as intraovarian regulators of follicular growth and atresia, suggesting that the fate of an individual follicle to develop to the preovulatory stage or to undergo atresia is associated with distinct profiles of steroid production. We therefore have localized 3 beta-hydroxysteroid dehydrogenase (3 beta-HSD), an enzyme required for the biosynthesis of all major steroid hormones, in ovaries of immature and adult rats during follicular development, atresia, and corpus luteum formation. The pattern of immunostaining for 3 beta-HSD remained constant in the interstitial cell compartment and was not affected by the age of the rats nor the stage of the estrous cycle. As thecal cells differentiated from the surrounding stroma and restructured around the secondary follicle, they expressed intense staining for 3 beta-HSD. This staining persisted in preantral, antral, and preovulatory follicles. Granulosa cells in primary, secondary, and antral follicles did not contain detectable levels of 3 beta-HSD and did not stain positively until the follicle reached the preovulatory stage of development. A novel finding presented in this paper is that 3 beta-HSD persisted in the thecal cells of follicles throughout the entire process of atresia, suggesting that during atresia the potential for the synthesis of androgens is retained.(ABSTRACT TRUNCATED AT 250 WORDS)

3-Hydroxysteroid Dehydrogenases↗

PubMed2002

Expression and localization of thrombospondin-1 and -2 and their cell-surface receptor, CD36, during rat follicular development and formation of the corpus luteum.

Thrombospondin (TSP)-1 and -2 are extracellular matrix glycoproteins that are both antiangiogenic and important in regulating cellular development, differentiation, and function. To evaluate the expression of TSP in follicular and luteal development, ovarian cycles of Sprague-Dawley rats were synchronized and tissues collected daily at stages corresponding to the early antral, ovulatory, early luteal, and late luteal phases of the ovarian cycle. Immunohistochemistry and Western blot analyses demonstrated that TSP-1 protein and its receptor, CD36, were present in the early antral phase and were localized primarily to the granulosa cells of antral follicles. Both proteins were also present immediately after ovulation and were localized to the developing corpus luteum. Messenger RNA for TSP-1 showed a similar pattern, with expression at the early antral and ovulatory phases. Protein and mRNA expression for TSP-2 was relatively delayed compared to TSP-1, although TSP-2 also was expressed in granulosa cells. Both TSP-1 and -2 were increased in response to LH stimulation in vitro, whereas TSP-2 was suppressed by FSH. The temporal pattern of expression of TSP-1, -2, and CD36, which mirrors the active phases of angiogenesis in this experimental model, is compatible with a role for these proteins in the control of ovarian vascularization.

Animals↗

PubMed2003

Expression and distribution of cyclooxygenase-2 in human ovary during follicular development.

Prostaglandins play important roles for oocyte maturation and follicular rupture. Cyclooxygenase-2 (COX-2), an inducible isoform of a prostaglandin metabolic enzyme, is essential for the timed production of prostaglandins in the ovary. The aim of the present study is to examine expression and distribution of COX-2 in human ovarian follicles at each of the maturation stages. Immunohistochemical staining shows that COX-2 is expressed in the granulosa cell layer of secondary and developing follicles, but is not detected in primary and Graafian follicles. Western blotting analysis revealed the existence of COX-2 in periovulatory follicular fluid at a mean concentration of 5.6 +/- 0.6 ng/ml. COX-2 might begin to be produced at the secondary follicle stage, and once a follicle reaches the Graafian follicle stage, the production of this enzyme is stopped. After exposure to luteinizing hormone (LH) surge, follicles might resume production of COX-2, and this is secreted into the follicular fluid.

Adult↗

PubMed1996

A follicular scoring system for monitoring ovulation induction in polycystic ovary syndrome patients based solely on ultrasonographic estimation of follicular development.

OBJECTIVE: To assess the predictive value of a follicular scoring system for monitoring ovulation induction in polycystic ovary syndrome (PCOS) patients, solely with ultrasound (US). DESIGN: Ultrasound measurements were performed on alternate days to define a serial follicular score for monitoring ovulation induction with hMG alone, as well as GnRH analogue and hMG, in comparison with E2 concentration obtained on the same day. SETTING: Outpatient Infertility Clinic, Department of Obstetrics and Gynecology. PATIENTS: Thirty-four consecutive PCOS patients treated for 63 cycles. MAIN OUTCOME MEASURE: The follicular score was established considering the summation of points obtained after measuring the mean diameter of each follicle > 5 mm, as follows: 5 to 8 mm = 1 point, 9 to 12 mm = 1.5 points, 13 to 16 mm = 2 points, > or = 17 mm = 3 points. RESULTS: Follicular score correlated positively with E2 concentrations. A score of > or = 30 points was associated with E2 levels of concentration that reached > 1,500 pg/mL (conversion factor to SI unit, 3.671) and could predict ovarian hyperstimulation. A lower follicular score allowed hCG administration. CONCLUSIONS: A follicular scoring system may be a safe, simple, and highly efficient method to replace serial E2 measurements in monitoring ovulation induction. Moreover, ovarian hyperstimulation may be predicted.

Adult↗

PubMed2001

A documented clomiphene-induced follicular development in pregnancy.

A case of clomiphene-induced follicular growth in pregnancy is presented in a 34-year-old woman with ectopic pregnancy treated at a university teaching hospital. Following administration of clomiphene citrate in pregnancy, follicular growth to 18 mm mean diameter was noted. It is concluded that clomiphene citrate can induce follicular growth and maturation in pregnancy, possibly by reversing pregnancy-induced pituitary suppression.

Adult↗

PubMed1984

Serum oestradiol and preovulatory follicular development before in-vitro fertilization.

Twenty-three in-vitro fertilization (IVF) treatment cycles (four unstimulated and 19 clomiphene-stimulated) were assessed retrospectively to discern relationships among serum oestradiol (OE2) titre on the day that human chorionic gonadotrophin (hCG) was given and the number and size of ovulatory follicles available for aspiration of oocytes during laparoscopy 32-38 h after hCG injection. Since 12 of the cycles succeeded to the stage of embryo replacement and two normal term pregnancies resulted, the series as a whole offers a useful referent data base. When only one ovulatory follicle developed (n = 8) the average volume of aspirated follicular fluid was approximately 6 ml, equivalent to a follicular diameter between 22 and 23 mm. When multiple follicles developed (mean 2.7/patient, n = 15), average fluid volume/follicle was not significantly different, averaging approximately 5.5 ml. Serum OE2 titre on the morning before hCG was injected ranged between 0.9 and 5.5 nmol/l and corresponded to the number of follicles aspirated at laparoscopy. There was a highly significant linear correlation (r = 0.85, P less than 0.001) between this OE2 value (X nmol/l) and total aspirated fluid volume (Y ml) where Y = 2.07 + 3.65 X. Thus taking 6 ml as the 'typical' fluid volume, the calibration line and its 95% confidence limits could be used to establish provisional 'ideal' pre-hCG serum OE2 titre ranges corresponding to the development of one, two or three mature ovulatory follicles. This information, combined with a knowledge of the number of presumptive preovulatory follicles present (assessed by ovarian ultrasound), can aid the timing of the hCG injection before IVF.

Adolescent↗

PubMed2000

Kinase pathways in dominant and subordinate ovarian follicles during the first wave of follicular development in sheep.

The mechanism by which one or more dominant ovarian follicles continue development while other subordinate follicles regress is not known. The mitogen activated protein kinases (MAPKs) are a group of kinases that are activated by hormonal factors and form a cascade of processes that regulate cell growth, division and differentiation. The aim of the present experiment was to characterise the presence of the MAPKs, Erk 1/Erk 2 and Akt in healthy dominant follicles and regressing subordinate follicles. Following in vivo monitoring of ovarian follicle development, three ewes were ovariectomised and the follicular fluid and follicle wall (theca and granulosa cells) saved from the dominant and largest subordinate follicle. The dissected diameter and follicular fluid oestradiol concentration of the dominant follicle was larger (P<0.01) than the largest subordinate follicle (6.5+/-0.0mm and 41.3+/-4.9ng/ml versus 4.7+/-0.3mm and 0.6+/-0.4ng/ml). Western blot analyses showed that there was more Akt (202.7+/-6.4 versus 59.6+/-32.7 units; P<0.05) and Erk 1/Erk 2 (104.5+/-10.6 versus 0.3+/-0.2 units; P<0.01) present in follicle wall samples from the dominant compared to the largest subordinate follicles. Phosphorylated forms of Akt and Erk 1/Erk 2 were detected in samples from dominant but not subordinate follicles. We suggest that signal transduction pathways involving Akt and Erk 1/Erk 2 may play an important role in determining the outcome of ovarian follicle growth and development in sheep.

Animals↗

PubMed1995

Follicular development and ovulation in sows: effect of hCG and GnRH treatment.

Follicular growth, chronology of ovulation and embryo morphology were compared in sows ovulating spontaneously and sows, in which the ovulation was attempted induced by hCG or GnRH. Indwelling catheters were placed on day 1 (weaning = day 0) in the ear veins of 18 sows, which were then randomly divided into 3 groups: a control group (N = 6), a group (N = 6) given 750 iu hCG (Physex) im 76h after weaning (hCG group) and a group (N = 6) given 500 micrograms GnRH (Fertagyl) im 76h (N = 3) or 100h after weaning (N = 3) (GnRH group). Follicular diameter and time of ovulation were monitored by ultrasonography every 4h from day 3 until ovulation or development of cysts by means of a sector scanner fitted with a 5.0/7.5 MHz multiangle probe. Heat detection was performed every 8h from day 3 until ovulation. On day 13, the sows were slaughtered, the number of corpora luteae (CL) was counted, and embryos were flushed from the uteri. The control group showed clear heat symptoms, and on day 3, the follicles were typically 3-7 mm and grew up to 7-10 mm over 2 days, where they remained for approximately 24h until ovulation took place 41h +/- 9h after first sign of standing heat. The hCG group exhibited no signs of heat, and the follicles only reached 5-8 mm in diameter at time of ovulation, which occurred 40h +/- 1h after hCG-injection. The GnRH group exhibited inconsistent signs of heat, and the follicles reached a maximum size of 7-12 mm in diameter where they remained for more than 24h. Only 2 sows in this group ovulated within 84-92h after the GnRH injection, and development of bursa cysts and cystic follicles was a common finding. The average number of CL was 18.2 +/- 5.7 per sow (N = 16, range: 3-27) with no significant difference between the groups. Total embryo recovery was 79 +/- 13% with no significant difference between groups. The embryo diversity calculated as standard deviation of the maximum diameter was higher in the hCG group as compared with the control group.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗

PubMed1983

Ultrasound monitoring of ovarian follicular development: a comparison real-time and static scanning techniques.

Follicular growth was monitored in 19 patients during 20 spontaneous and induced cycles by different examiners in a blind trial using a real-time linear array, a mechanical sector scanner, and a gray scale compound scanner. This was done to compare the efficacy of different ultrasound equipment in the study of ovarian cycle. The mean maximum follicular diameter was calculated with each equipment and the quality of follicular images was classified as poor, sufficient, and good as defined in the study. The overall best results in ovary and follicle visualization were achieved with the real-time sector scanner. Measurements of the same dominant follicle using realtime and compound scanners were highly correlated (linear array/compound scanner: r = 0.894, p less than 0.001; sector/compound scanner: r = 0.928, p less than 0.001). Following ovulation, some unexpected differences in the distribution of the postovulatory patterns were noted with each instrument. Except in difficult patients, real-time examination, preferably performed using a sector scanner, appears to be the optimal first ultrasonic approach for monitoring follicular growth.

Female↗