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Biomedical subjects

B C Fauser

Publications and source records attributed to B C Fauser.

At least 55 records · Page 3Linked to original sources
PubMed1999

Progress in ovarian stimulation.

It is uncertain whether patients who do not ovulate but fail to conceive following CC therapy behave differently during gonadotropin therapy. However, if the infertile patient with PCOS is resistant to anti-estrogen therapy, gonatropin treatment administered through low dose protocols should be considered. As compared to conventional regimens, complication rates are reduced despite similar efficacy. It should be recognized that patients with PCOS constitute a very heterogeneous group. Therapy outcome may benefit from improved classification. The identification of clinical characteristics that identify those women with anovulation who are unlikely to respond to clomiphene would permit earlier use of gonadotropin therapy and potentially offer major health and economic benefits. Furthermore, if ovarian responsiveness to ovulation-induction therapy could be predicted for an individual patient, it might be possible to devise regimens that reduced the risk of ovarian hyperstimulation and multiple pregnancy.

Clomiphene↗
PubMed1998

Developmental and endocrine aspects of normal ovarian aging.

Supplies of follicles are established during early fetal life and decrease exponentially thereafter by a process called atresia. Subfertility only starts at a mean age of about 30-31 years, when the remaining follicle reserve has become a fraction of its original number. Thereafter, a further decrease in both oocyte quantity and quality dictates the subsequent reproductive events including decrease of fertility, increased abortion rate, the end of fertility, the beginning of cycle irregularity and, when almost no follicles are left, the occurrence of menopause. The same remarkable variation of age at menopause almost certainly is also present for the preceding reproductive events. When quantity and quality of antral follicles drop below a critical threshold, there is a subsequent drop in inhibine B resulting in the selective FSH rise at a mean age of 37-38 years. This FSH rise explains the accelerated follicle depletion, the increased proportion of growing follicles reaching the selectable stage, the shortening of the follicular phase and the increased incidence of dizygotic twinning. The concurring decrease of oocyte quality is in line with the increased incidence of abortions and chromosomal aberrations after age 35.

Aging↗
PubMed1998

Follicle development during the normal menstrual cycle.

An understanding of the factors which determine initiation of follicle growth, recruitment and dominant follicle selection may increase our understanding of the underlying process of ovarian aging. In this article, these aspects of the normal menstrual cycle are reviewed. The morphological and endocrinological development in the early follicle is described from the primordial follicle stage. The degree of follicle-stimulating hormone (FSH) dependency is discussed, as is the relationship of estradiol (E2) production to follicle diameter. The principles governing mono-follicular selection are outlined, and the FSH 'threshold' and 'window' concepts are highlighted. Maximum FSH levels in the early follicular phase are shown to be variable between individuals. The relevance of this and the means by which individual sensitivity to FSH may be altered at the ovary in the context of ovarian aging are discussed.

Aging↗
PubMed1998

Recombinant follicle-stimulating hormone (FSH; Puregon) is more efficient than urinary FSH (Metrodin) in women with clomiphene citrate-resistant, normogonadotropic, chronic anovulation: a prospective, multicenter, assessor-blind, randomized, clinical trial. European Puregon Collaborative Anovulation Study Group.

OBJECTIVE: To compare the safety and efficacy of recombinant FSH (follitropin beta, Puregon; NV Organon, Oss, the Netherlands) and urinary FSH (urofollitropin, Metrodin; Ares-Serono, Geneva, Switzerland). DESIGN: A prospective, multicenter, assessor-blind, randomized, clinical trial. SETTING: Twelve European infertility clinics. PATIENT(S): One hundred seventy-two women (recombinant FSH: n = 105; urinary FSH: n = 67) with clomiphene citrate-resistant normogonadotropic chronic anovulation (World Health Organization group II). INTERVENTION(S): Eligible subjects were randomized (ratio of recombinant to urinary FSH, 3:2) and treated for a maximum of three cycles. A low-dose step-up regimen was used, with 75 IU of FSH given IM daily for a maximum of 14 days and, if needed, weekly increments of half an ampule given thereafter until the threshold dose for follicular development was achieved. MAIN OUTCOME MEASURE(S): Cumulative ovulation rate after three cycles, total FSH dose, and treatment period needed to achieve ovulation. RESULT(S): The cumulative ovulation rates after three treatment cycles were 95% and 96% for the recombinant and urinary FSH groups, respectively. Overall, ovulation was seen in 155 of 223 treatment cycles (69.5%) in the recombinant FSH group, compared with 92 of 138 treatment cycles (66.7%) in the urinary FSH group. In the first cycle, a statistically significantly lower total dose (750 versus 1,035 IU) and a shorter treatment period (10 versus 13 days) were needed in the recombinant FSH group to reach ovulation. Only one case of ovarian hyperstimulation syndrome led to hospitalization. Two sets of twins (one in each treatment group) and one set of triplets (in the recombinant FSH group) were born. CONCLUSION(S): Recombinant FSH (Puregon) is more efficient than urinary FSH (Metrodin) in inducing follicular development.

Adult↗
PubMed1998

High dose gonadotrophin-releasing hormone antagonist (ganirelix) may prevent ovarian hyperstimulation syndrome caused by ovarian stimulation for in-vitro fertilization.

This case report describes the first attempt to treat imminent ovarian hyperstimulation syndrome (OHSS) by using a gonadotrophin-releasing hormone (GnRH) antagonist. A 33 year old, normo-ovulatory woman undergoing in-vitro fertilization received daily subcutaneous injections of 150 IU of recombinant follicle-stimulating hormone (recFSH) from cycle day 2, together with GnRH antagonist (ganirelix) 0.125 mg from cycle day 7 onwards. On cycle day 10 the patient was found to have a serum oestradiol concentration of 16 500 pmol/l and, on ultrasound examination, four preovulatory (>16 mm) and nine intermediate sized (10-16 mm) follicles. RecFSH injections were discontinued, human chorionic gonadotrophin (HCG) withheld, whereas the ganirelix dose was increased to 2 mg/d. This regimen led to a rapid decrease in serum oestradiol concentrations and the decrease in ovarian size on ultrasound. Since GnRH antagonists will become clinically available for in-vitro fertilization programmes in the near future this suggested regimen might have a role in preventing severe OHSS.

Adult↗
PubMed1998

Lack of correlation between maximum early follicular phase serum follicle stimulating hormone concentrations and menstrual cycle characteristics in women under the age of 35 years.

The gradual increase in follicle stimulating hormone (FSH) concentrations in women approaching menopause results from the depletion of the ovarian follicular pool, a process referred to as 'ovarian ageing'. This study investigates whether variable endogenous FSH concentrations, as have been observed in normo-ovulatory young women, are related to menstrual cycle characteristics, including predictors of ovarian ageing. Serum concentrations of immunoreactive FSH, oestradiol, and inhibin-A and inhibin-B were measured, and follicular growth was assessed by transvaginal ultrasound throughout the follicular phase in 39 healthy volunteers (20-35 years) with regular menstrual cycles. Median serum FSH concentration on cycle day 3 was 5.1 IU/l (range 3.6-11.2), and median maximum follicular phase FSH was 6.2 IU/l (range 4.3-11.2), observed on cycle day 6 (range 2-15). Maximum FSH concentrations were not correlated with age or cycle length, nor with maximum inhibin-B. The number of small (<10 mm) antral follicles on cycle day 3 was 11 (range 4-21) and was not correlated with age, nor with maximum FSH. Inhibin-A remained low until a significant rise on cycle day 9 (range 3-12), which was significantly correlated with the late follicular rise in oestradiol (r = 0.56, P = 0.01). These observations indicate a lack of correlation between maximum follicular phase serum FSH concentrations and parameters of ovarian ageing in women under the age of 35 years. In addition, FSH concentrations assessed on cycle day 3 represent an underestimation of maximum early follicular phase FSH. Distinct individual differences in intra-ovarian modification of FSH action, resulting in differences in the FSH threshold for stimulation of ovarian function, may be operative.

Adult↗
PubMed1998

Developments in human recombinant follicle stimulating hormone technology: are we going in the right direction?

Recent developments in recombinant DNA technology have enabled the large scale production of human recombinant follicle stimulating hormone (rFSH); and this compound has recently been introduced to the market. Understanding of the structure-function relationship of FSH isohormones is crucial in understanding discussions on the standardization procedures of gonadotrophin preparations, potential differences in clinical efficacy of the various gonadotrophin preparations and in comprehending future developments (long-acting and short-acting forms, and rFSH preparations with altered isohormone profiles). Differences between immunoreactive and bioactive serum FSH concentrations have been observed following the administration of rFSH. Accordingly, the isohormone distribution of rFSH is similar to, but not identical with, natural human FSH. Issues relevant to daily practice discussed in this review include: the total absence of urinary contaminants allowing for the safe s.c. administration of the compound. Production is independent from urine, and the capacity can be adjusted according to clinical needs. The relationship between serum oestradiol concentrations and number and size of follicles observed by ultrasound may change when rFSH is combined with gonadotrophin-releasing hormone (GnRH) agonist, due to low serum lueinizing hormone (LH) concentrations. In the case of endogenous serum LH concentrations within the normal range, exogenous administration of LH is redundant. In the near future, rFSH preparations with altered bioactivity will be available.

Animals↗
PubMed1998

The follicle-stimulating hormone (FSH) threshold/window concept examined by different interventions with exogenous FSH during the follicular phase of the normal menstrual cycle: duration, rather than magnitude, of FSH increase affects follicle development.

According to the threshold concept, FSH concentrations need to surpass a distinct level to stimulate ovarian follicle growth. The window concept stresses the significance of a limited duration of elevated FSH levels above the threshold for single dominant follicle selection. The aim of this study was to investigate effects on follicle growth of increased FSH levels, differing in duration and magnitude of elevation, during the follicular phase. Twenty-three normo-ovulatory (cycle length, 26-31 days), young (age, 20-31 yr) women volunteered for this study. In all subjects a series of daily transvaginal sonography scans of the ovaries and blood sampling [for FSH and estradiol (E2) determinations] were performed during two consecutive cycles. The first study cycle (control cycle) started 10 days after urinary assessment of the LH surge in the preceding cycle (DayLH) and was concluded on the day of ovulation assessed by transvaginal sonography scans. The second series of daily monitoring (intervention cycle) started 10 days after DayLH in the control cycle. After randomization, subjects received either 375 IU urinary FSH, s.c., as a single injection on Day(LH+14) (group A; n = 11) or 75 IU daily from Day(LH+19) until Day(LH+23) (group B; n = 12). In group A, FSH levels increased on the day after injection to a median concentration of 10.1 IU/L, which was 1.9 times higher (P < 0.01) than levels on matching days during the control cycle. Concentrations returned to basal levels 3 days after injection. In group B, a moderate elevation of FSH concentrations (15% increase; P < 0.05) was observed compared to levels during the control cycle. In group A, E2 concentrations increased (P = 0.03) 1 day after FSH injection and returned to baseline levels within 2 days. In group B, E2 levels started to increase after the first injection of FSH and remained significantly higher (P < 0.01) during the following 5 days compared to those on matching days in the control cycle. Compared to matching days in the control cycle an increased number of follicles 8-10 mm in size was found in group A (P < 0.01) during the period from Day(LH+14) until Day(LH+19), without an increase in follicles 10 mm or larger thereafter. In contrast, in group B, the numbers of both 8- to 10-mm and 10-mm or larger follicles were higher during the period from Day(LH+19) until Day(LH+24) in group B (P = 0.02 and P < 0.01, respectively). Results from the present study suggest that a brief, but distinct, elevation of FSH levels above the threshold in the early follicular phase does not affect dominant follicle development, although the number of small antral follicles did increase. In contrast, a moderate, but continued, elevation of FSH levels during the mid to late follicular phase (effectively preventing decremental FSH concentrations) does interfere with single dominant follicle selection and induces ongoing growth of multiple follicles. These findings substantiate the FSH window concept and support the idea of enhanced sensitivity of more mature follicles for stimulation by FSH. These results may provide the basis for further investigation regarding ovulation induction treatment regimens with reduced complication rates due to overstimulation.

Adult↗
PubMed1998

Predictors of patients remaining anovulatory during clomiphene citrate induction of ovulation in normogonadotropic oligoamenorrheic infertility.

The diagnostic criteria used to identify patients suffering from polycystic ovary syndrome remain controversial. The present prospective longitudinal follow-up study was designed to identify whether certain criteria assessed during standardized initial screening could predict the response to ovulation induction with clomiphene citrate (CC) in 201 patients presenting with oligomenorrhea or amenorrhea and infertility. Serum FSH levels were within the normal range (1-10 IU/L), and all patients underwent spontaneous or progestin-induced withdrawal bleeding. Initial CC doses were 50 mg daily for 5 days starting on cycle day 3. In the case of an absent response, doses were increased to 100 and 150 mg daily in subsequent cycles. First ovulation with CC was used as the end point. After a complete follow-up (in the case of a nonresponse, at least 3 treatment cycles with daily CC doses up to 150 mg), 156 patients (78%) ovulated. The free androgen index (FAI = testosterone/sex hormone-binding globulin ratio), body mass index (BMI), cycle history (oligomenorrhea vs. amenorrhea), serum androgen (testosterone and/or androstenedione) levels, and mean ovarian volume assessed by transvaginal sonography were all significantly different (P < 0.01) in responders from those in nonresponders. FAI was chosen to be the best predictor in univariate analysis. The area under the receiver operating characteristics curve in a multivariate prediction model including FAI, BMI, cycle history, and mean ovarian volume was 0.82. Patients whose ovaries are less likely to respond to stimulation by FSH due to CC treatment can be predicted on the basis of initial screening characteristics, such as FAI, BMI, cycle history (oligomenorrhea or amenorrhea), and mean ovarian volume. These observations may add to ongoing discussion regarding etiological factors involved in ovarian dysfunction in these patients and classification of normogonadotropic anovulatory infertile women.

Adult↗
PubMed1997

Classification of normogonadotropic infertility: polycystic ovaries diagnosed by ultrasound versus endocrine characteristics of polycystic ovary syndrome.

OBJECTIVE: To investigate the predictive value of polycystic ovaries for endocrine signs of polycystic ovary syndrome (PCOS). DESIGN: Controlled descriptive study. SETTING: Academic tertiary care fertility clinic. PATIENT(S): Normogonadotropic (FSH levels between 1 and 10 mIU/mL conversion factor to SI unit, 1.0) oligomenorrheic or amenorrheic women visiting our fertility clinic and a control group of regularly cycling, healthy, normal weight volunteers recruited by advertisement. INTERVENTION(S): Single blood samples and transvaginal sonography were performed. MAIN OUTCOME MEASURE(S): Serum levels of FSH, LH, androstenedione (A), and T and ovarian volume, ovarian stroma density, and follicle number. RESULT(S): In control women, the 95th percentile was calculated for ovarian volume, follicle number, and stroma count as well as endocrine parameters. The use of these upper limits of normal in the study group resulted in 217 (66%) patients with polycystic ovaries on ultrasound (defined as increased mean ovarian volume and/or mean follicle number per ovary), whereas only 120 (36%) patients exhibited elevated serum androgens (increased A and/or T concentrations) and 155 (47%) showed elevated LH levels. Sensitivity and specificity of single or combined sonographic parameters for prediction of elevated serum LH or androgen concentrations were limited. CONCLUSION(S): In the study group of normogonadotropic oligomenorrhea or amenorrheic infertile women, we set strict cutoff levels for various criteria used in the literature for defining PCOS. Groups defined by sonographic or endocrine PCOS criteria did overlap, but sonographic parameters had limited predictive value for abnormal hormone serum levels.

Adult↗
PubMed1997

Insulin-like growth factors and insulin-like growth factor binding proteins in androgen-dominant ovarian follicles from testosterone-treated female-to-male trans-sexuals.

OBJECTIVE: To determine insulin-like growth factor (IGF)-I and IGF-II levels, IGF binding protein (IGFBP) profile, and IGFBP-4 protease activity in androgen-dominant follicular fluid (FF) from female-to-male trans-sexuals and to compare with those in follicles from normocycling women. DESIGN: Follicular fluid samples were obtained from four female-to-male trans-sexuals and 15 women with normo-ovulatory cycles at the Dijkzigt Academic Hospital. Western ligand blot analysis and protease assays were used to determine IGFBP profile, and immunoradiometric assays were used to detect IGF levels. SETTING: The study was performed in two academic medical centers. PATIENT(S): Female-to-male trans-sexuals and women with normo-ovulatory cycles. INTERVENTIONS: None. MAIN OUTCOME MEASURE(S): Determination of IGF levels and IGFBP profile. RESULT(S): Insulin-like growth factor I levels in FF from female-to-male trans-sexuals were not significantly different compared with levels in androgen-dominant FF and estrogen-dominant FF. Significantly lower levels of IGF-II were observed in FF from female-to-male trans-sexuals than in estrogen-dominant FF, whereas IGF-II levels in FF from female-to-male trans-sexuals were not significantly different than those in androgen-dominant FF. Similar IGFBP profiles from FF from female-to-male trans-sexuals and androgen-dominant FF were noted, with markedly elevated levels of the 31- and 24-kd IGFBPs and a 28-kd IGFBP, compared with estrogen-dominant FF. An IGFBP-4-specific metalloserine protease that is active in estrogen-dominant FF likewise was undetected in FF from female-to-male trans-sexuals. CONCLUSION(S): Follicles developing under the influence of exogenous androgens in ovaries in female-to-male trans-sexuals appear to be similar to androgen-dominant follicles in normo-ovulatory women with regard to IGF-I and IGF-II levels, IGFBP profile, and the absence of IGFBP-4 protease activity.

Androgens↗
PubMed1997

Urinary follicle-stimulating hormone for normogonadotropic clomiphene-resistant anovulatory infertility: prospective, randomized comparison between low dose step-up and step-down dose regimens.

A low dose step-up and step-down regimen for induction of ovulation using urinary FSH was compared in a prospective randomized fashion in 37 normogonadotropic clomiphene-resistant oligo- or amenorrheic infertile women. The objectives was to assess potential differences in duration of treatment, ovarian stimulation (serum FSH levels), and response [serum estradiol (E2) levels and number and size of follicles]. Monitoring (blood sampling and transvaginal sonography) took place on the day of initiation of treatment, the first day of ovarian response as assessed by ultrasound (i.e. the first day a follicle > or = 10 mm could be recognized), the day of hCG administration to induce ovulation, and 3 days thereafter. The median duration of treatment in the low dose step-up group was 18 (range, 7-41) days compared to 9 (range, 4-16) days in the step-down group (P = 0.003), and the total numbers of ampules administered were 20 (range, 7-69) and 14 (range, 7-33), respectively (P = NS). Serum FSH levels from the first day of sonographic ovarian response until the administration of hCG were constant (median increase, 2%/day) in patients receiving the low dose step-up protocol, but showed a decrease (median, 5%/day) in step-down cycles (P < 0.001). Monofollicular growth, defined as not more than one follicle 16 mm or larger on the day of hCG administration, was observed in 56% of low dose step-up and 88% of step-down cycles (P = 0.04). The percentage of patients with normal range periovulatory E2 serum levels (500-1500 pmol/L) was 33% in the low dose step-up group vs. 71% in the step-down group (P = 0.03). We conclude that a step-down protocol for gonadotropin induction of ovulation exhibits a more physiological, late follicular phase FSH serum profile than a low dose step-up protocol. This results in a shorter duration of treatment, a greater number of monofollicular cycles, and more cycles with periovulatory E2 levels within the normal range in the step-down protocol.

Adult↗
PubMed1997

Low levels of follicle-stimulating hormone receptor-activation inhibitors in serum and follicular fluid from normal controls and anovulatory patients with or without polycystic ovary syndrome.

In patients with normogonadotropic anovulation, either with or without polycystic ovary syndrome (PCOS), factors interfering with FSH action may be involved in arrested follicle development. The aim of this study is to assess whether factors inhibiting FSH receptor activation are elevated in serum or follicular fluid from anovulatory patients, as compared with regularly cycling women. For this purpose, a Chinese hamster ovary cell line, stably transfected with the human FSH receptor, has been applied. FSH-stimulated cAMP secretion in culture medium was measured in the presence of serum or follicular fluid. Chinese hamster ovary cells were stimulated with a fixed concentration of FSH (3 or 6 mIU/mL) to mimic FSH levels in serum or follicular fluid. Samples were added in concentrations ranging from 3-90% vol/vol to approach protein concentrations occurring in serum or follicular fluid. In the presence of 10% vol/vol serum from regularly cycling women (n = 8), FSH-stimulated cAMP production was inhibited to 42 +/- 2% (mean +/- SEM of 2 experiments, each performed in duplicate) of cAMP production in the absence of serum, whereas a similar cAMP level (up to 38 +/- 4% of the serum-free level) was observed at higher concentrations of serum (30-90% vol/vol). The inhibition of FSH-stimulated cAMP production in the presence of serum samples from normogonadotropic anovulatory patients, without (n = 13) or with (n = 16) PCOS, was similar to controls. Follicular fluid samples (n = 57) obtained during the follicular phase in 25 regularly cycling women and follicular fluid samples (n = 25) from 5 PCOS patients were tested in a slightly modified assay system. In the presence of 10 or 30% (vol/vol) follicular fluid, FSH-stimulated cAMP levels were decreased to 68 +/- 2% and 55 +/- 2% (mean +/- SEM of a single experiment in triplicate) of the cAMP levels in the absence of follicular fluid, respectively. There was no correlation between the degree of cAMP inhibition and follicle size, steroid content (androstenedione or estradiol concentrations), or menstrual cycle phase. Furthermore, no differences in inhibition were found, comparing PCOS follicles with size- and steroid content-matched follicles obtained during the normal follicular phase. It is concluded that inhibition of FSH receptor activation by proteins present in serum or follicular fluid is constant (60 and 40%, respectively) and independent from the developmental stage of the follicle, either during the normal follicular phase or in patients with normogonadotropic anovulation. Inhibition of FSH receptor activation may be of limited significance for normal and arrested follicle development.

Adult↗
PubMed1996

Effects of two doses of tibolone on trabecular and cortical bone loss in early postmenopausal women: a two-year randomized, placebo-controlled study.

The present randomized, double-blind, placebo-controlled, 2-year study is the first to evaluate the effect of 1.25 and 2.5 mg tibolone daily oral administration on trabecular and cortical bone loss in early postmenopausal women. Ninety-four healthy, normal weight, nonsmoking women participated 1-3 years following spontaneous menopause. Twenty-three subjects were randomized to the placebo group, 36 to the 1.25 mg/day tibolone group, and 35 to the 2.5 mg/day tibolone group. Bone density was assessed at 6 month intervals. Spinal trabecular bone density (BD) was measured with quantitative computed tomography. Phalangeal cortical BD was measured by radiographic absorptiometry. The 2-year change vs. baseline in the placebo group for trabecular BD was -6.4% (95% confidence interval -8.1 to -4.7). Cortical BD did not change significantly. At 24 months both tibolone groups showed a statistically significantly higher trabecular [9.4% (6.6-12.2) for the 1.25 mg group and 14.7% (11.8-17.5%) for the 2.5 mg group] and phalangeal BD [4.4% (1.5-7.4) for the 1.25 mg group and 6.8% (3.8-9.8) for the 2.5 mg group] as compared to the placebo group. After 2 years of tibolone in both regimes, trabecular and phalangeal BD was significantly higher as compared to pretreatment values. At 24 months the 2.5 mg group showed a significantly higher trabecular (p < 0.001) but not phalangeal (p = 0.064) BD compared to the 1.25 mg group. Tibolone prevents early postmenopausal bone loss by inducing an increase in trabecular and phalangeal BD.

Absorptiometry, Photon↗
PubMed1996

Normal human follicle development: an evaluation of correlations with oestradiol, androstenedione and progesterone levels in individual follicles.

OBJECTIVE: The mechanism of dominant follicle selection remains obscure. We have investigated the association between follicle diameter and follicular steroid levels in individual human ovarian follicles throughout the menstrual cycle. DESIGN: Fluid from ovarian follicles (n = 326) was obtained in vivo during surgery from 55 regularly cycling women with proven fertility. Follicles were divided into dominant (diameter >9 mm, n = 45) and non-dominant (diameter < or = 9 mm, n = 281) based on ultrasound measurements. MEASUREMENTS: Fluid was assayed for oestradiol (E2), androstenedione (AD), and progesterone (P). RESULTS: Median P and E2 levels were significantly lower (P < 0.0001) and AD levels significantly higher (P = 0.03) in non-dominant as compared to dominant follicles. In non-dominant follicles AD (r = 0.14, P = 0.02), but not P and E2, levels were correlated to follicular diameter, and significant changes in steroid concentrations across the menstrual cycle were absent. In dominant follicles, diameter was positively correlated with P and E2 (P < 0.001) levels, and inversely correlated with AD concentrations (P = 0.01). CONCLUSIONS: Results indicate that (1) intrafollicular oestradiol concentrations rise only in follicles exceeding 9 mm in diameter and correlate with the diameter of these dominant follicles, suggesting that significant increase in aromatase enzyme activity occurs only in the dominant follicle (2) a cycle-independent accumulation of androstenedione with size occurs in non-dominant follicles, and (3) progesterone production occurs in the largest dominant follicles only, suggesting a limited, if any, role for progesterone during follicle development.

Adult↗
PubMed1996

Circulating immunoreactive and bioactive follicle stimulating hormone concentrations in anovulatory infertile women and during gonadotrophin induction of ovulation using a decremental dose regimen.

Our purpose was to determine whether decreased follicle stimulating hormone (FSH) activity, either systemic or at the follicular level, is involved in impaired follicle growth associated with normogonadotrophic anovulation. To differentiate between the possible levels of disturbance, bioactive (BIO-FSH; using the in-vitro rat granulosa cell aromatase bioassay) and immunoreactive (IRMA-FSH) FSH serum concentrations of three groups of subjects were compared: (i) 172 normogonadotrophic anovulatory infertile women during baseline conditions, (ii) 22 clomiphene-resistant polycystic ovary syndrome patients undergoing ovulation induction by exogenous gonadotrophins using a decremental dose regimen, and (iii) nine regularly cycling controls. BIO-FSH [13.2 (range 0.8-29.5) IU/l] and IRMA-FSH [4.4 (range 1.2-9.3) IU/l] concentrations in anovulatory women during baseline conditions were significantly lower than maximum concentrations reached during the follicular phase in controls [18.7 (13.2-23.4) and 6.4 (5.7-10.0) IU/l respectively], but were not significantly different from initial concentrations in controls [10.4 (7.2-19.6) and 4.8 (2.8-8.2) IU/l respectively]. Moreover, concentrations of IRMA-FSH and BIO-FSH were negatively correlated (r = -0.25, P = 0.01, and r = -0.24, P = 0.02 respectively) with the interval between last vaginal bleeding and blood sampling. Maximum concentrations of IRMA-FSH [7.6 (3.9-10.9) IU/l] during ovulation induction by gonadotrophins were not significantly different from maximum [6.4 (5.7-10.0) IU/l] concentrations in controls, whereas maximum BIO-FSH concentrations [13.5 (8.7-17.4) versus 18.7 (13.2-23.4) IU/l] were significantly lower. Our findings suggest that (i) circulating FSH does not reach concentrations that are sufficient to induce normal follicle development in anovulatory women during baseline conditions, and (ii) the FSH threshold for ovarian stimulation of this patient group is not different from normal.

Adult↗
PubMed1996

Interference with follicle stimulating hormone regulation of human ovarian function.

This review summarizes observations on the background and potential clinical significance of interference with follicle stimulating hormone (FSH) regulation of human ovarian function. This interference may occur at the level of the pituitary by the secretion of FSH isoforms with reduced or absent bioactivity. In addition, interference with FSH may occur in the circulation, or within the ovarian follicular compartment. Although the full range of its significance remains to be elucidated, there are distinct indications that these mechanisms may be involved in normal ovarian physiology, as well as in abnormal response of the ovary to stimulation by endogenous FSH or by exogenously-administered gonadotrophin preparations. Moreover, recent advances in the determination of the structure-function relationship of FSH and FSH-receptor interaction, in combination with new developments in recombinant DNA technology, will allow the production of modified FSH- or FSH receptor-like molecules with altered bioactivity. The availability of FSH agonists and antagonists in the near future should provide a challenge for clinicians to improve treatment outcome and to find new indications for the use of these compounds.

Female↗