Impact of obesity and leptin levels on the secretion of estradiol,inhibin A and inhibin B during ovarian stimulation with gonadotropins

We examined the impact of high leptin levels on the secretion of estradiol, inhibin A and inhibin B in obese and lean women during ovarian stimulation. Patients undergoing long-term pituitary suppression, ovarian stimulation and in vitro fertilization for non-endocrine reasons were included in this case-control study. Obese women (body mass index (BMI) > 28 kg/m²; n = 17) were individually matched with lean women (BMI 20-25 kg/m²; n = 17) for age and baseline follicle stimulating hormone and luteinizing hormone concentrations. Blood samples were collected in a previous menstrual cycle and 1–3 days apart throughout ovarian stimulation. Serum levels of estradiol, leptin, inhibin A and inhibin B were measured. Obese and lean women had similar serum concentrations of estradiol, inhibin A and inhibin B in the follicular and luteal phases of the spontaneous menstrual cycle, and throughout ovarian stimulation. Serum levels of leptin were higher in obese than in lean women, and increased during stimulation in both groups. In the obese group, area-under-the-curve (AUC) leptin levels correlated with AUC inhibin A levels. In the lean group, there was no correlation between AUC leptin levels and AUC levels of ovarian hormones. The results suggest that high leptin concentrations in vivo are not associated with impaired secretion of estradiol and dimeric inhibins during ovarian stimulation.     

Neuropeptide Y, leptin, galanin and insulin in women with polycystic ovary syndrome.

It has been reported that polycystic ovary syndrome (PCOS) is very frequently associated with obesity, insulin resistance and hyperinsulinemia. However, metabolic disorders may lead to suppression of reproductive hormone secretion during undernutrition and in obesity. Some neuropeptides, such as neuropeptide Y (NPY) and galanin, modulate the control of appetite and play an important role in the mechanism of luteinizing hormone-releasing hormone (LHRH) secretion. NPY and galanin regulate appetite via both central and peripheral mechanisms. The interaction between central and peripheral signals for the control of food intake is due to leptin. Leptin can modulate the activity of NPY and other peptides in the hypothalamus that are known to affect eating behavior. In order to evaluate the relationship between NPY, galanin and leptin, 28 women with PCOS, 32 obese women (non-PCOS) and 19 lean healthy women (control group) were investigated. Obese women with PCOS were divided into two groups: PCOS (A) overweight (body mass index, BMI 26-30 kg/m2), and PCOS (B) obese (BMI 31-40 kg/m2). Plasma NPY, galanin and leptin concentrations were measured by radioimmunoassay. Plasma leptin levels in obese women with PCOS (groups A and B) were significantly higher than those in the control group (p < 0.05, p < 0.05, respectively). A significant positive correlation between plasma leptin and BMI in women with PCOS was found (r = 0.427, p < 0.01). A positive correlation was demonstrated between leptin and testosterone in PCOS (r = 0.461, p < 0.01). Plasma galanin concentrations in PCOS were higher than in the control group but the differences were not significant. Plasma NPY levels were significantly elevated in both non-obese (normal) and obese women with PCOS (group A) (p < 0.01, p < 0.005, respectively). However, in obese non-PCOS women plasma NPY levels gradually increased with increase in BMI. No significant correlations were found between galanin, NPY and percentage change in response of LH to LHRH, as well as between NPY and insulin, and galanin and testosterone. Plasma insulin concentrations in women with PCOS (group B) were significantly higher than in the control group (p < 0.001). Increased plasma NPY levels are found in both obese and non-obese women with PCOS. The increase in NPY is independent of the increase in BMI. In obese women with PCOS, plasma leptin is increased compared with control lean women. Serum insulin concentration is increased in obese women with PCOS. A positive correlation exists between leptin and BMI as well as between leptin and testosterone in women with PCOS. These results may suggest that the feedback system in the interaction between leptin and NPY is disturbed in PCOS.     

Basal leptin concentrations in women with normal and dysfunctional ovarian conditions.

OBJECTIVE: To determine whether leptin is involved in ovarian function. METHODS: Fasting serum samples were obtained from 20 women with normal menstrual cycles who were either obese or non-obese: 12 non-obese patients with polycystic ovary syndrome (PCOS), 8 obese patients with PCOS, 10 patients with stress-related hypothalamic amenorrhea, and 8 patients with weight loss-related hypothalamic amenorrhea. RESULTS: Serum leptin levels were strongly related to body mass index (BMI) in each group, but there was no difference in the mean serum leptin levels among the BMI-matched study groups. A significant difference in the mean serum leptin levels was found between the non-obese and obese control groups (P<0.001) and between the non-obese and obese PCOS groups (P<0.001). CONCLUSIONS: These findings indicate that circulating leptin levels in women with normal menstrual cycles and those with ovarian dysfunction are strongly related to BMI. Leptin does not appear to be primarily involved in regulating ovarian function.     

Abnormal inhibin A and inhibin B secretion in obese women with and without insulin resistance.

AIM: The present study aimed to establish inhibin A and B serum levels during the menstrual cycle of obese women, and its usefulness as an index of luteal-phase follicular development. MATERIALS AND METHODS: Twenty-one obese patients (mean body mass index: 34.9+/-3.7 kg/m2; range: 30.0-45.0 kg/m2) were submitted to basal hormonal measurements and an oral glucose tolerance test after challenge with 75 g glucose. Progesterone and inhibin A and B levels were determined 5-7 days after the menstrual cycle and 7 days prior to expected menses. RESULTS: As expected, an increase in inhibin A and a decrease in inhibin B were observed when first-phase samples were compared with samples obtained after 15-20 days. On the other hand, the percentage variation of both inhibin A and B was at least four times smaller than the values for normal women described previously by other authors employing the same enzyme-linked immunosorbent assays. A small number of obese women presented ovulatory cycles characterized by progesterone concentration higher than 5.8 ng/ml. The percentage elevation (>190%) of inhibin A in the second samples was in agreement with the progesterone levels, but it seemed to be more sensitive for the detection of follicle luteinization. CONCLUSION: We conclude that obese women present less percentage variation of both inhibin A and B during the menstrual cycle, associated with a low frequency of ovulatory cycles. In obese women, the percentage increase of inhibin A can represent an additional marker to recognize follicle luteinization.     

Concentrations of inhibins and activin in women undergoing stimulation with recombinant follicle-stimulating hormone for in vitro fertilization treatment

OBJECTIVE: To investigate the influence of human recombinant follicle-stimulating hormone (FSH) on circulating serum concentrations of the ovarian proteohormones inhibin A, inhibin B, pro alpha-C, and activin A and serum levels of estradiol after down-regulation with GnRH analogue. DESIGN: Serum concentrations of ovarian proteohormones and estradiol. SETTING: Academic clinical practice. PATIENT(S): 30 women who underwent assisted reproductive techniques. INTERVENTION(S): Blood samples were analyzed for inhibin A, inhibin B, pro alpha-C, activin A, and estradiol during IVF treatment at points coinciding with pituitary down-regulation, stimulation with recombinant FSH, ovulatory triggering, and the luteal phase of the cycle. RESULT(S): Activin A levels did not change with recombinant FSH stimulation. In women with a sonographically detected leading follicle >17 mm in diameter, levels of inhibin A, pro alpha-C, and estradiol increased significantly (P<.05). The increase in inhibin B level was not statistically significant. In patients without adequate follicle development during FSH stimulation, serum levels of inhibins remained low and did not significantly deviate from values measured before stimulation. CONCLUSION(S): Inhibin A and pro alpha-C are effective markers of follicular development and may be effective additions to estradiol as a marker.     

Mast cell distribution and density in the normal uterus--metachromatic staining using lectins

OBJECTIVE: To investigate the correlation between the early follicular phase serum inhibin B levels and other indicators of ovarian reserve. STUDY DESIGN: Seventy-four women aged 24-40 years (mean 32) with different infertility etiologies were investigated in the early follicular phase of a spontaneous mentrual cycle. The volume of the ovaries was measured and the total number of follicles <5 mm in size counted by ultrasound. Serum levels of FSH, estradiol (E2) and inhibin B were measured on the same day. In stepwise regression analysis inhibin B levels were correlated with age, body-mass-index, the ultrasound measurements, cause of infertility, parity, FSH and E2. RESULTS: FSH, BMI and the number of follicles proved to be statistically significant independent predictive factors for the inhibin B levels, FSH and BMI correlating negatively and the number of follicles positively with inhibin B serum concentrations. CONCLUSION: The number of small follicles reflect the inhibin B production of the ovaries. BMI being as strong predictive factor of inhibin B levels as FSH could in part explain the impaired likelihood of conceiving in obese patients.     

Abnormal inhibin A and inhibin B secretion in obese women with and without insulin resistance

Aim.?The present study aimed to establish inhibin A and B serum levels during the menstrual cycle of obese women, and its usefulness as an index of luteal-phase follicular development.

Materials and methods.?Twenty-one obese patients (mean body mass index: 34.9?±?3.7?kg/m²; range: 30.0–45.0?kg/m²) were submitted to basal hormonal measurements and an oral glucose tolerance test after challenge with 75?g glucose. Progesterone and inhibin A and B levels were determined 5–7 days after the menstrual cycle and 7 days prior to expected menses.

Results.?As expected, an increase in inhibin A and a decrease in inhibin B were observed when first-phase samples were compared with samples obtained after 15–20 days. On the other hand, the percentage variation of both inhibin A and B was at least four times smaller than the values for normal women described previously by other authors employing the same enzyme-linked immunosorbent assays. A small number of obese women presented ovulatory cycles characterized by progesterone concentration higher than 5.8?ng/ml. The percentage elevation (?>?190%) of inhibin A in the second samples was in agreement with the progesterone levels, but it seemed to be more sensitive for the detection of follicle luteinization.

Conclusion.?We conclude that obese women present less percentage variation of both inhibin A and B during the menstrual cycle, associated with a low frequency of ovulatory cycles. In obese women, the percentage increase of inhibin A can represent an additional marker to recognize follicle luteinization.     

The effect of hypophysectomy on inhibin production by adult rat ovaries: Changes in ovarian inhibin gene expression and serum inhibin

Our aim was to determine whether serum leptin level is regulated by thyroid hormones ,lipid metabolic products and insulin resistance status in women with polycystic ovary syndrome (PCOS). A prospective case-controlled study was carried out in Istanbul University ,Cerrahpasa School of Medicine in 25 lean PCOS (L-PCOS) women ,19 obese PCOS (O-PCOS) women and 28 normal women. The diagnosis of PCOS was established according to the clinical ,hormonal (elevated luteinizing hormone and serum androgens) and ultrasonographic findings. Fasting serum levels of thyroid stimulating hormone (TSH) ,free triiodothyronine (FT3), free thyroxine (FT4) ,fasting glucose ,insulin ,total cholesterol (TC) ,triglyceride (TG) ,high-density lipoprotein-cholesterol (HDL-C) ,low-density lipoprotein-cholesterol (LDL-C) ,very low-density lipoprotein-cholesterol (VLDL-C) and leptin were measured and compared in the three groups and the correlations between serum levels of leptin and other parameters were evaluated. Serum leptin levels were higher in the O-PCOS group ,while its level was comparable between the L-PCOS and control groups. Serum levels of FT4 were significantly lower in both L-PCOS and O-PCOS groups than the control group. Women in both L-PCOS and O-PCOS groups were found to be significantly hyperinsulinemic and insulin resistant. Serum levels of TC ,VLDL-C and TG were significantly higher in the O-PCOS group ,while serum HDL-C level was lower. There was a poor correlation between serum leptin ,and FT4 ,TC ,TG ,HDL-C and VLDL-C levels. A significant correlation was observed between serum leptin levels and both BMI and insulin resistance status in PCOS. We believe that ,although thyroid hormones and lipid metabolic products do not seem to participate in the regulation of serum leptin levels ,BMI and insulin resistance status may have a key role in women with PCOS.     

Serum inhibin A, inhibin B, pro-alphaC, and activin A levels in women with idiopathic premature ovarian failure

Serum inhibin A, inhibin B, pro-alphaC, and activin A levels in 30 women with idiopathic premature ovarian failure (POF), 30 postmenopausal women, and 30 age-matched fertile women were determined. Women with POF showed low levels of inhibin A and inhibin B, but not of activin A, whereas the levels of pro-alphaC were significantly higher than in postmenopausal women. Thus, the circulating level of pro-alphaC could be a marker for assessing residual ovarian function in women with POF.     

Serum inhibin B correlates with successful ovulation in infertile women

Purpose : To investigate whether inhibin B and activin A serum and follicular fluid levels in infertile women undergoing induction of superovulation correlate with successful ovulation. Methods : Infertile women (n = 16) (30–43 years of age) undergoing induction of superovulation for assisted reproduction were studied. A blood sample was collected before and days 3, 8, and 12 during the induction of superovulation. A follicular fluid sample at the time of ovarian pick up was also collected. Serum and follicular fluid were assayed for inhibin B, activin A, and estradiol. Results : According to the successful follicular development women were divided in two groups: (A) responders (n = 10) and (B) poor responders (n = 6). Women of group A showed mean follicular fluid inhibin B levels higher than in group B (P = 0.001), while no significant difference for activin A levels was found. During induction of superovulation serum activin A levels did not change in both groups of women, while inhibin B and estradiol levels significantly increase only in responder women (P < 0.001). Serum inhibin B and estradiol levels correlated with follicles developed 10 mm (P = 0.000). Conclusions : Serum inhibin B is an effective marker of follicular development in infertile women undergoing induction of superovulation, and may represent a further marker for ovarian follicular capacity.     

The role of inhibin B as a basal determinant of ovarian reserve

Our objective was to compare inhibin B and conventional basal determinants in designating the ovarian reserve in patients receiving assisted reproductive treatment. A total of 58 women ,aged 19–47 years ,who were accepted for assisted reproductive treatment at the Zeynep Kamil Women and Children's Hospital ,Department of Assisted Reproductive Technologies ,were included in the study. The age ,body mass index ,basal levels of follicle stimulating hormone ,estradiol and inhibin B ,volume of the ovary and number of antral follicles were compared prospectively. When the number of oocytes collected was ≥ 5 ,this was accepted as a sufficient ovarian response. Serum inhibin B (cut-off level 56 pg/ml) ,as a basal determinant of ovarian reserve ,had the highest sensitivity (81%) and specificity (81%). The usefulness of serum inhibin B measurement as a basal determinant of ovarian reserve is supported.     

Relationships between circulating leptin concentrations and other hormonal parameters in obese and non-obese women with polycystic ovary syndrome

Aim: To clarify the role of leptin in women with polycystic ovary syndrome (PCOS), we analyzed whether serum leptin levels correlate with other hormonal parameters in obese and non-obese women with PCOS.
Methods: We studied 20 obese (body mass index, BM ≥25 kg/m²) and 20 non-obese (BMI <25 kg/m²) women with PCOS diagnosed by the existence of menstrual disturbance, elevated serum level of luteinizing hormone (LH) with normal follicle-stimulating hormone (FSH) and the characteristic polycystic appearance of the ovaries on transvaginal ultrasound images. Blood samples for LH, FSH, estradiol, testosterone (T), androstenedione (Δ₄) and leptin were obtained, and the relationships between variables were examined by calculating Spearman correlation coefficients.
Results: Mean levels of leptin, T and Δ₄ in obese PCOS women were significantly higher than those in non-obese PCOS women, but this was not the case for BMI, bodyweight and waist to hip ratio. In all the 40 PCOS women considered together, there were significant positive correlations of leptin with BMI, waist to hip ratio, and Δ₄ levels. However, in each group separately, serum leptin levels in obese PCOS women correlated only with BMI and bodyweight, whereas serum leptin levels in non-obese PCOS women correlated with serum A4 levels.
Conclusion: Although further study is needed to assess the role of leptin on ovarian function in non-obese women with PCOS, present findings do not support the fact that leptin is involved in the development of hormonal abnormalities in obese women with PCOS. (Reprod Med Biol 2002; 1 : 49–54)     

The role of inhibin B as a basal determinant of ovarian reserve.

Our objective was to compare inhibin B and conventional basal determinants in designating the ovarian reserve in patients receiving assisted reproductive treatment. A total of 58 women, aged 19-47 years, who were accepted for assisted reproductive treatment at the Zeynep Kamil Women and Children's Hospital, Department of Assisted Reproductive Technologies, were included in the study. The age, body mass index, basal levels of follicle stimulating hormone, estradiol and inhibin B, volume of the ovary and number of antral follicles were compared prospectively. When the number of oocytes collected was > or = 5, this was accepted as a sufficient ovarian response. Serum inhibin B (cut-off level 56 pg/ml), as a basal determinant of ovarian reserve, had the highest sensitivity (81%) and specificity (81%). The usefulness of serum inhibin B measurement as a basal determinant of ovarian reserve is supported.     

Short-term human chorionic gonadotropin-induced testosterone rise does not modify leptin levels in eugonadal men.

The aim of this study was to monitor serum leptin concentrations after altering the levels of testosterone, by intramuscular administration of human chorionic gonadotropin (hCG), in eugonadal men. A 7-day monitoring of hCG, testosterone and leptin levels was performed after intramuscular administration of a dose of 5000 IU hCG in these men. Thirty fertile men aged 23-38 years were studied. In addition, 30 women aged 18-34 years with normal ovulatory cycles were studied, to verify reports of sexual dimorphism in serum leptin levels. These 60 individuals were divided into four groups, according to their sex and body mass index (BMI) values. In men, blood samples were collected at 09.00, after an overnight fast, for the determination of hCG, testosterone and leptin levels, and, immediately thereafter, a dose of 5000 IU hCG was administered intramuscularly. Further blood samples were collected at 24-h intervals for a period of 7 days for determination of the same hormones. In women, blood samples were collected only once, at 09.00, after an overnight fast between the 3rd and the 6th day of the menstrual cycle, for determination of serum estradiol and leptin levels. Our results showed that the mean value of leptin in thin men and women was significantly lower than that in obese men and women, respectively. The mean value of leptin in thin women was significantly higher than that in obese men. Serum leptin concentrations decreased significantly, 168 h after short-term hCG administration. There was a significant positive correlation between BMI values and serum leptin concentrations, in both men and women. Our results support the view that hCG administration in eugonadal men does not influence serum leptin levels. Moreover, a short-term increase of serum testosterone levels, after one dose of hCG, is not sufficient to affect and modify leptin secretion mechanisms in vivo.     

Short-term human chorionic gonadotropin-induced testosterone rise does not modify leptin levels in eugonadal men

The aim of this study was to monitor serum leptin concentrations after altering the levels of testosterone, by intramuscular administration of human chorionic gonadotropin (hCG), in eugonadal men. A 7-day monitoring of hCG, testosterone and leptin levels was performed after intramuscular administration of a dose of 5000 IU hCG in these men. Thirty fertile men aged 23-38 years were studied. In addition, 30 women aged 18-34 years with normal ovulatory cycles were studied, to verify reports of sexual dimorphism in serum leptin levels. These 60 individuals were divided into four groups, according to their sex and body mass index (BMI) values. In men, blood samples were collected at 09.00, after an overnight fast, for the determination of hCG, testosterone and leptin levels, and, immediately thereafter, a dose of 5000 IU hCG was administered intramuscularly. Further blood samples were collected at 24-h intervals for a period of 7 days for determination of the same hormones. In women, blood samples were collected only once, at 09.00, after an overnight fast between the 3rd and the 6th day of the menstrual cycle, for determination of serum estradiol and leptin levels. Our results showed that the mean value of leptin in thin men and women was significantly lower than that in obese men and women, respectively. The mean value of leptin in thin women was significantly higher than that in obese men. Serum leptin concentrations decreased significantly, 168 h after short-term hCG administration. There was a significant positive correlation between BMI values and serum leptin concentrations, in both men and women. Our results support the view that hCG administration in eugonadal men does not influence serum leptin levels. Moreover, a short-term increase of serum testosterone levels, after one dose of hCG, is not sufficient to affect and modify leptin secretion mechanisms in vivo.     

Elaboration of a working model for the involvement of inhibin A as a mediator of the preovulatory rise of progesterone levels.

During the final days of follicular development, exogenously administered follicle-stimulating hormone (FSH) produces a rise in serum progesterone level. The aim of the present study was to investigate the possible source and regulation of this preovulatory progesterone surge. Four sets of matching treatments with gonadotropins for in vitro fertilization and intracytoplasmic sperm injection were selected from a cohort of 953 treatments in 244 couples. Half of these four sets of treatments were selected based on the unusual course of the progesterone concentration during follicular development. The first set of 11 cycles with early termination of gonadotropin administration for prolonged coasting were compared with a set of 12 cycles with similar estradiol levels but with uninterrupted ovarian stimulation. Another set of 12 cycles with low preovulatory progesterone levels (<2 nmol/l) were matched with ten cycles with normal preovulatory progesterone levels (>2 nmol/l). The sera of these four selected sets of treatments were stored for subsequent measurement of the concentrations of inhibin A, inhibin B, activin A and leptin. During ovarian hyperstimulation serum levels of inhibin A correlated significantly with those of progesterone (p < 0.001), whereas this correlation disappeared after the withdrawal of FSH administration. The rapid fall of progesterone levels during prolonged coasting contrasts with the continuing rise of estradiol concentration and indicates that the theca interna, not the granulosa, is the major source of preovulatory progesterone. Women failing to produce any increment of progesterone levels at the end of follicular development had significantly lower levels of inhibin A (p < 0.05), indicating that inhibin A may well be involved in mediating the signal of FSH from the granulosa to the theca interna.     

The influence of obesity on ovarian function. II. Plasma leptin concentration in women with polycystic ovary syndrome

OBJECTIVES: The aim of the present study was to estimate the leptin role in the pathogenesis of polycystic ovary syndrome. DESIGN: The study was carried out in 21 obese women with PCO, 18 obese women without menstrual disturbances and 9 normal-weight healthy women. MATERIALS AND METHODS: In all patients antropomethric parameters: weight, height, % of body fat, waist and hip girths were measured and than BMI and WHR were calculated. Plasma concentrations of leptin, insulin, LH, FSH, testosterone, cortisol, PRL, estradiol were estimated. RESULTS: There were no statistical significant difference between plasma leptin concentrations in obese patients with PCO in comparison to obese women with normal menstrual cycle. In both groups of obese patients plasma leptin concentrations was significantly higher than in control group (p < 0.001, p < 0.001). There were significant correlation between plasma leptin and % body fat, BMI and waist girth in all studied groups. CONCLUSIONS: We conclude that leptin is not directly involved in observed hormonal disturbances in polycystic ovary syndrome. The main predictor of plasma leptin concentrations in patients with PCO is amount of body fat.     

Luteal-phase inhibin A and follicular-phase inhibin B levels are not characteristic of patients with an elevated LH-to-FSH ratio

Purpose: To test whether serum inhibin levels are related to differences in gonadotropin concentrations between patients with an elevated LH-to-FSH ratio (ELF patients) and controls. Methods: 32 ELF patients were matched with controls by age, body mass index (BMI), and cycle length. Results: No statistically significant difference was found in follicular-phase inhibin B levels or midluteal inhibin A levels between cases and controls. Significant negative correlation was observed between follicular-phase inhibin B concentrations and BMI in ELF patients but not among controls. LH and FSH were positively related to inhibin B levels in ELF patients. Midluteal inhibin A correlated with sex hormone-binding globulin in controls but not in ELF patients. Conclusions: Neither follicular-phase inhibin B levels nor midluteal inhibin A levels are characteristic of patients with an elevated LH-to-FSH ratio. Opposite correlations with LH and BMI suggest dysregulation of inhibin secretion rather than dimeric inhibins having a central role to the endocrinological imbalance observed in polycystic ovary syndrome.Presented in part at the 18th Annual Meeting of the European Society for Human Reproduction and Embryology, Vienna, Austria, June 30 to July 3, 2002.     

Serum inhibin A, inhibin B, and pro-alphaC levels are altered after surgically or pharmacologically induced menopause

OBJECTIVE: To evaluate the course of changes in serum inhibin A, inhibin B, and pro-alphaC levels in women with surgically or pharmacologically induced menopause. DESIGN: Longitudinal study. SETTING: Academic Health Center of Siena, Siena, Italy. PATIENT(S): Four groups of women were studied: [1] surgical menopause including bilateral oophorectomy (n = 15), [2] amenorrhea induced by GnRH-analogue for treatment of endometriosis (n = 13), [3] amenorrhea induced by antineoplastic chemotherapy before (n = 15) and after chemotherapy (n = 13), and [4] control physiological menopause (n = 67). INTERVENTION(S): Collection of blood specimens. MAIN OUTCOME MEASURE(S): Serum inhibin A, inhibin B, and pro-alphaC concentrations were measured by using specific two-site ELISAs. RESULT(S): Following oophorectomy, serum inhibin A, inhibin B, and pro-alphaC levels were decreased on the first postoperative day; on the fifth postoperative day they were still significantly reduced. Women with amenorrhea induced by GnRH-analogue treatment exhibited serum inhibin A and pro-alphaC levels that were significantly higher than those observed in physiological menopause. Patients undergoing antineoplastic chemotherapy had higher serum inhibin A levels than those in physiological menopause, whereas inhibin B and pro-alphaC levels did not differ. During the course of chemotherapy, median serum inhibin A concentrations were similar to those of patients evaluated after the suspension of treatment. In postmenopause, inhibin A, and inhibin B levels were low, whereas levels of pro-alphaC were still detectable. CONCLUSION(S): Circulating levels of inhibin A, inhibin B, and pro-alphaC are reduced after oophorectomy. Women with amenorrhea induced by GnRH-analogue treatment or by antineoplastic chemotherapy still produce inhibin A and pro-alphaC. This probably reflects a residual ovarian function and hormone synthesis. Therefore, the ovary may be a source of pro-alphaC after menopause; significant amounts of pro-alphaC are present in circulation after natural menopause, but not after oophorectomy.     

Serum leptin level across different phases of menstrual cycle in normal weight and overweight/obese females

We compared serum leptin levels during various phases of menstrual cycle and its correlation with serum estradiol between normal weight and overweight/obese young females. Fifty-six young females with normal menstrual cycle were grouped into 26 normal weight and 30 overweight/obese subjects. Serum leptin and estradiol levels were measured during early follicular, pre-ovulatory and luteal phases of menstrual cycle in both groups using ELISA technique. Serum leptin levels were significantly different across different phases of menstrual cycle with a steady increment from follicular phase (9.97?±?5.48?ng/dl) through pre-ovulatory phase (11.58?±?6.49?ng/dl) with their peaks in luteal phase (12.52?±?6.39?ng/dl, p?相似文献