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Biomedical subjects

M Filicori

Publications and source records attributed to M Filicori.

At least 55 records · Page 3Linked to original sources
PubMed1988

Alterations of the hypothalamic GnRH interpulse interval sequence over the normal menstrual cycle.

Luteinizing hormone (LH) is released in a pulsatile fashion from the anterior pituitary in response to hypothalamic gonadotropin-releasing hormone (GnRH) secretion. Previous autocorrelation analysis of the sequence of interpulse intervals of LH secretion in normal men has supported the hypothesis that the underlying hypothalamic mechanism of GnRH secretion governing episodic LH release is a renewal process, indicating that hypothalamic "memory," if present, does not extend back further in time than the preceding secretory pulse. A similar analysis of pulsatile LH secretion was undertaken in 45 studies of normal women, obtained throughout the menstrual cycle. Analysis of these studies revealed a process consistent with renewal throughout the follicular and early luteal phases. However, this relationship appears to break down in the mid-to-late luteal phase, indicating that alternative feedback pathways provide an overriding influence on the underlying renewal process of hypothalamic GnRH secretion. Pulsatile progesterone secretion by the corpus luteum, which first emerges at this stage of the menstrual cycle, may be the agent responsible for this feedback.

Female↗
PubMed1988

Hyperfunction of the hypothalamic-pituitary axis in women with polycystic ovarian disease: indirect evidence for partial gonadotroph desensitization.

To examine gonadotropin secretory frequency as a component of the disordered neuroendocrine regulation of gonadotropin secretion in women with polycystic ovarian disease (PCOD), we measured serum gonadotropin concentrations in 12 women with PCOD at 10-min intervals for periods of 12-24 h. The patterns of LH and FSH release in these patients were compared to the findings of 24 studies in 21 age-matched normal women during the early, mid- and late follicular phases (EFP, MFP and LFP) of their cycles. Serum sex steroid levels during the 12-24 h of study in the women with PCOD were compared to those in normal women studied during the follicular phase. The mean serum estradiol (E2) level in the women with PCOD was similar to that in normal women studied in the EFP, but lower than those in normal women in the MFP (P less than 0.05) and LFP (P less than 0.01). Mean serum estrone, however, was significantly higher in women with PCOD than in women in the EFP and MFP (P less than 0.05 and P less than 0.02, respectively), but lower than that in women in the LFP (P less than 0.02). Total and unbound testosterone (T) levels were significantly elevated in women with PCOD compared to those in normal women at all stages of the follicular phase (P less than 0.001). The mean serum LH concentration and LH pulse amplitude were markedly elevated in the women with PCOD compared to normal women at all three stages of the follicular phase (P less than 0.05 or less). In addition, LH pulse frequency was faster in women with PCOD [24.8 +/- 0.9 ( +/- SE) pulses/24 h] than that in women in the EFP (15.6 +/- 0.7; P less than 0.01), MFP (22.2 +/- 1.1; P less than 0.05) and LFP (20.8 +/- 1.2; P less than 0.01). This increased LH pulse frequency in women with PCOD correlated with ambient serum E2 levels on the day of study (r = 0.84; P less than 0.001), but not with serum estrone, T, or unbound T. Repeat studies in four women with PCOD demonstrated a similarly abnormal gonadotropin secretory pattern in each. We conclude that 1) women with PCOD have an increase in both the amplitude and frequency of LH secretion compared to those in normally cycling women throughout the follicular phase; 2) the defect in women with PCOD is reproducible.(ABSTRACT TRUNCATED AT 400 WORDS)

Adult↗
PubMed1988

Gonadotropin-releasing hormone (GnRH) analog suppression renders polycystic ovarian disease patients more susceptible to ovulation induction with pulsatile GnRH.

Pulsatile GnRH administration consistently restores normal reproductive hormone levels and ovulation in women with hypogonadotropic hypogonadism, but is less effective in those with polycystic ovarian disease (PCOD). We pharmacologically created a hypogonadotropic condition with a GnRH analog (GnRH-A) in six women with PCOD to investigate the role of deranged gonadotropin secretion in PCOD and to improve the response to pulsatile GnRH ovulation induction. Before GnRH and GnRH-A treatment the women with PCOD had increased LH pulse frequency [one pulse every 55 +/- 2 (+/- SE) min; P less than 0.05] and LH pulse amplitude (10.9 +/- 1.4 U/L; P less than 0.05) compared to normal women in the follicular phase of their menstrual cycle. Each PCOD woman completed one cycle of pulsatile GnRH administration for ovulation induction before (pre-A cycles; n = 6) and one or two cycles after (post-A cycles; n = 9) GnRH-A administration [D-Ser(tBu)6-Des,Gly10-GnRH; 300 micrograms, sc, twice daily for 8 weeks]. Pulsatile GnRH (5 micrograms/bolus) was given at 60-min intervals using a Zyklomat pump. Daily blood samples were drawn during the pulsatile GnRH ovulation induction cycles for the determination of serum LH, FSH, estradiol (E2), progesterone, and testosterone, and pelvic ultrasonography was done at 1- to 4-day intervals. Mean (+/- SE) serum LH levels were elevated during the pre-A cycle (49.2 +/- 3.1 IU/L) and decreased to normal levels during the post-A cycles (19.6 +/- 1.4 IU/L; P less than 0.0001). Mean testosterone concentrations were lower during the post-A cycles [88 +/- 2 ng/dL (3.1 +/- 0.1 nmol/L)] than during the pre-A cycles [122 +/- 3 ng/dL (4.2 +/- 0.1 nmol/L); P less than 0.0001]. In the follicular phase of the post-A cycles E2 levels were significantly lower [81 +/- 5 pg/mL (300 +/- 20 pmol/L) vs. 133 +/- 14 pg/mL (490 +/- 50 pmol/L); P less than 0.0001], preovulatory ovarian volume was smaller (24.6 +/- 2.0 vs. 31.4 +/- 2.4 cm3; P less than 0.01), and the FSH to LH ratio was higher (0.56 +/- 0.03 vs. 0.16 +/- 0.01) than in the pre-A cycle, suggesting more appropriate function of the pituitary-gonadal axis. Excessive LH and E2 responses to pulsatile GnRH administration in the early follicular phase of the pre-A cycle were abolished in the post-A cycles.(ABSTRACT TRUNCATED AT 400 WORDS)

Adult↗
PubMed1988

GnRH agonists and antagonists. Current clinical status.

Gonadotrophin-releasing hormone (GnRH) analogues offer a novel approach for the non-steroidal manipulation of the reproductive endocrine axis. GnRH agonists are now effectively employed in the management of precocious puberty, prostate and breast cancer, endometriosis, uterine leiomyoma, polycystic ovarian disease, and various other disorders. Unfortunately, contraceptive applications of GnRH agonists have been disappointing. The availability of slow release depot formulations of GnRH agonists, and the development of GnRH antagonists may further optimise and extend the clinical application of these compounds.

Humans↗
PubMed1986

Triplet pregnancy after low-dose pulsatile gonadotropin-releasing hormone in polycystic ovarian disease.

In a patient with polycystic ovarian disease, low-dose intravenous pulsatile gonadotropin-releasing hormone (5 mcg every hour) and no exogenous human chorionic gonadotropin induced multiple follicular development and elevated estrogen levels and resulted in a triplet pregnancy. Patients with polycystic ovarian disease may have a higher risk of complications and should be monitored more closely during ovulation induction with pulsatile gonadotropin-releasing hormone.

Adult↗
PubMed1986

Hypogonadotropic disorders in men and women: diagnosis and therapy with pulsatile gonadotropin-releasing hormone.

Hypogonadotropic hypogonadism (HH) is a clinical syndrome occurring in both sexes which has long puzzled clinicians due to the apparent paradox of nonfunctioning gonads in the face of normal or only slightly lowered levels of circulating gonadotropins. Using frequent sampling of gonadotropin levels as an index of hypothalamic GnRH secretion, we have examined the hypothesis that this group of disorders represents a spectrum of abnormal patterns of the pulsatile release of endogenous GnRH. After a broad, normative data base was established in both men and women for purposes of comparison, it appears that quantifiable abnormalities of GnRH secretion are discernible in both males and females with HH. These abnormalities include a total absence of GnRH secretion, defects of the amplitude and frequency of its secretion, and altered bioactivity of the gonadotropins released. In addition, physiological regimens of hypothalamic replacement therapy with exogenous GnRH, which are fashioned to mimic the normal frequency of endogenous GnRH secretion, result in complete normalization of reproductive function and fertility in hypogonadotropic subjects of both sexes. Thus, the heterogeneous nature of HH, as well as its favorable clinical and biochemical responses to GnRH, suggest that the basic defect in this family of disorders involves a partial or complete inability to synthesize and/or release GnRH from the hypothalamus in a manner compatible with physiological reproductive function. Conversely, these findings imply that maintenance of a physiological amplitude and frequency of endogenous GnRH secretion appear to be essential for normal reproductive function.

Adolescent↗
PubMed1986

Intravenous administration of pulsatile gonadotropin-releasing hormone in hypothalamic amenorrhea: effects of dosage.

Eighteen women with well characterized hypothalamic amenorrhea underwent 30 cycles of pulsatile GnRH treatment in an effort to examine the role of GnRH dosage in pituitary and ovarian responses. GnRH was administered iv at 2 doses (25 and 100 ng/kg bolus) at a physiological range of frequencies (90 and 60 min) in the follicular phase of the induced cycles. After demonstration of ovulation by ultrasound and clinical parameters, the frequency of GnRH administration was progressively slowed from every 60 min to every 90 min and then to every 240 min to mimic the slowing of endogenous LH secretion that occurs during the luteal phase in normal women. The results of these induced cycles were compared to those of 62 ovulatory cycles from normal women. Overall clinical and biochemical results revealed the following. Patients receiving doses of 25 ng/kg GnRH successfully ovulated only 80% of the time, with recruitment of a single dominant follicle. Two of 5 patients became pregnant. Peak estradiol levels were significantly lower than normal [261 +/- 33 (+/- SE) vs. 342 +/- 11 pg/ml, respectively; P less than 0.02]. Integrated luteal phase progesterone production was also significantly reduced in the 25 ng/kg group compared to normal (78 +/- 17 vs. 145 +/- 8 ng/ml/entire luteal phase, respectively; P less than 0.02). All women receiving bolus doses of 100 ng/kg GnRH ovulated; maturation of multiple follicles occurred in 5 of 20 cycles, and 6 of 7 women conceived. Peak estradiol values were significantly higher than those in either normal women or the 25 ng/kg group (478 +/- 48 pg/ml; P less than 0.02 for both), with integrated luteal phase progesterone levels significantly higher than those in patients receiving the 25 ng/kg dose (196 +/- 25 ng/ml/luteal phase; P less than 0.02). This study demonstrates that ovulation and fertility can be achieved with a physiological frequency regimen of pulsatile GnRH administration using bolus doses of both 25 and 100 ng/kg in women with hypothalamic amenorrhea; the 25 ng/kg dose of GnRH may represent a threshold of stimulation of the pituitary-ovarian axis and recreates cycles with an inadequate luteal phase; and a 100 ng/kg dose of GnRH may well cause a supraphysiological stimulation of the pituitary-gonadal axis.

Amenorrhea↗
PubMed1986

Characterization of the physiological pattern of episodic gonadotropin secretion throughout the human menstrual cycle.

To characterize the spectrum of pulsatile gonadotropin secretion during the course of the normal menstrual cycle, we studied normal women during 51 ovulatory cycles. Plasma gonadotropin concentrations were measured at 10-min intervals for 20-24 h during the early, mid-, and late follicular phases and the early, mid-, and late luteal phases. LH data series were analyzed using 2 different computer-assisted algorithms for pulse detection. The LH interpulse interval decreased during the follicular phase (FP) from 94 +/- 4 (+/- SEM) min in the early FP (EFP) to 71 +/- 4 min by the late FP (LFP; P less than 0.001). The estimation of LH pulse frequency in the EFP was significantly affected by slowing of episodic LH secretion during sleep. In the luteal phase (LP), the LH interpulse interval progressively increased from 103 +/- 8 min in the early LP (ELP) to 216 +/- 39 min by the late LP (LLP; P less than 0.001). Sleep-associated slowing of episodic LH secretion also occurred in the ELP. The mean LH pulse amplitude in the EFP (6.5 +/- 0.4 mIU/ml) decreased significantly by the midfollicular phase (MFP; 5.1 +/- 0.8 mIU/ml; P less than 0.05) and increased once again by the LFP (7.2 +/- 1.2 mIU/ml). LH pulse amplitude was highest in the ELP (14.9 +/- 1.7 mIU/ml), decreased by the midluteal phase (MLP) to 12.2 +/- 2.0 mIU/ml, and declined further by the LLP to 7.6 +/- 1.1 mIU/ml (P less than 0.001 vs. ELP). FSH secretion was significantly (P less than 0.05) correlated with LH secretion at time lags of 0-10 min in 82% of the studies. These results indicate the following. 1) In the EFP and ELP, the frequency of gonadotropin pulsations is reduced at night in association with sleep. 2) The frequency of LH secretion increases from the EFP to MFP and LFP. 3) LH pulse amplitude decreases in the MFP, suggesting enhanced negative feedback of estrogen on the hypothalamic-pituitary axis and/or a decrease in GnRH secretion at this stage. 4) A progressive reduction of LH pulse frequency and amplitude occurs during the LP which is correlated with the duration of exposure of the hypothalamic-pituitary axis to progesterone. 5) A close relationship exists between secretion of LH and FSH, suggesting a common stimulatory factor for both gonadotropins.

Adolescent↗
PubMed1986

Gonadotropin-releasing hormone (GnRH) physiology in men and women.

The combined approach used in studies of GnRH secretion provided a complimentary array of techniques with which to establish the program of amplitude (dose) and frequency of GnRH secretion in the physiologic state. Normative data in men and women were useful in formulating frequency estimates, which could then be applied to the task of replacement of GnRH in deficient (IHH) individuals. Comparison of the results of therapy with these 'ablation-replacement' models then allowed to arrive closer to the true amplitude or dose of exogenous GnRH required to duplicate the physiologic ideal. In addition to providing insight into the neuroendocrine control of reproduction, these applications provided treatment of various reproductive disorders in men and women. Further expansion of the efforts into other potential defects of endogenous GnRH secretion will ultimately uncover those disorders amenable to therapy.

Adolescent↗
PubMed1984

ELISA for salivary and plasma estriol in pregnancy.

A competitive, sensitive, and rapid enzyme-linked immunoadsorbent assay (ELISA) was developed for the determination of estriol in saliva and in plasma. Horseradish peroxidase (HRP) was used as the label enzyme; separation between free and bound steroid was carried out by insolubilized antibody prepared by adsorbing purified IgG of rabbit anti-6-oxoestriol-6-(O-carboxymethyl)oxime-BSA on polystyrene balls. The enzyme activity was measured by a colorimetric reaction using o-phenylenediamine dihydrochloride and hydrogen peroxide as substrate. The sensitivity of the assay was 12 pg/tube. In order to compare ELISA to RIA estriol estimations in different biological fluids, we selected six women during normal pregnancy, from the 30th to the 40th week of gestation. Salivary estriol was assayed by direct and extraction methods, while the corresponding plasma samples of the same subjects were analyzed only for unconjugated estriol by an extraction method. A good agreement was found between the results obtained by RIA and ELISA: r = 0.897, p less than 0.001 between direct RIA and direct ELISA in saliva; r = 0.909, p less than 0.001 between extraction RIA and direct ELISA in saliva; and r = 0.916, p less than 0.001 between extraction RIA and extraction ELISA in plasma. A good correlation (r = 0.793, p less than 0.001) was present between plasma samples by RIA and saliva samples by ELISA (direct method). These results indicate that: ELISA is a reliable method for the determination of estriol in plasma and saliva. Saliva samples can be used for the assay of estriol and therefore for the assessment of fetal conditions during pregnancy.

Enzyme-Linked Immunosorbent Assay↗
PubMed1984

Neuroendocrine regulation of the corpus luteum in the human. Evidence for pulsatile progesterone secretion.

The pattern of episodic gonadotropin release was studied in 15 normal female volunteers during the luteal phase of the menstrual cycle with 24 h of blood sampling for follicle-stimulating hormone (FSH) and luteinizing hormone (LH) levels at 10-min intervals. Six subjects (two in the early, two in the mid-, and two in the late luteal phase) also had each of these specimens processed for progesterone levels. A progressive slowing of LH pulsations was present across the luteal phase with the mean LH pulse frequency declining from 15.2 pulses/24 h in the early to 8.4/24 h in the late luteal phase. A trend towards reduction in the amplitude of LH pulses was also observed (12.3 +/- 2.2 SD mIU/ml in the early vs. 8.6 +/- 3.4 mIU/ml in the late luteal phase; NS). In addition, LH pulses of heterogeneous amplitude were identified during the same 24-h study. The mean +/- SD of the larger and of the smaller LH pulses was 16.9 +/- 4.7 and 2.3 +/- 1.0 mIU/ml, respectively (P less than 0.001). While the slowing of the frequency of all LH pulses correlated well (r = 0.80, P less than 0.001) with the day of the luteal phase and poorly with the actual plasma progesterone levels, the incidence of the small LH pulses was highest in the mid-luteal phase and correlated well with the mean progesterone plasma levels (r = 0.63, P less than 0.01). In the early luteal phase, the pattern of progesterone secretion was stable over the 24-h studies and showed no relationship to episodic LH release. In contrast, in the mid- and late luteal phase, plasma progesterone concentrations rapidly fluctuated during the 24-h studies from levels as low as 2.3 to peaks of 40.1 ng/ml, often within the course of minutes. Progesterone increments closely attended episodes of LH release, as documented by the significant (P less than 0.05) cross-correlation between LH and progesterone levels, at time lags of 25-55 min. The results of this study indicate that in the human luteal phase: (a) the frequency of pulsatile release of LH declines progressively and correlates well with the duration of exposure to progressively and correlates well with the duration of exposure to progesterone; (b) the amplitude of LH pulses varies with the appearance of an increased percentage of smaller pulses correlating well with the acute level of progesterone; (c) in the early luteal phase, the pattern of progesterone secretion is stable; (d) in the mid- and late luteal phase, progesterone secretion is episodic, and correlates with LH pulsatile release; and (e) single progesterone estimations in the mid- and late luteal phase do not accurately reflect corpus luteum adequacy.

Corpus Luteum↗
PubMed1984

The study of GnRH control of reproductive function.

The activity of the hypothalamic-pituitary-gonadal (HPG) axis is controlled by gonadotropin-releasing hormone (GnRH). GnRH, gonadotropins, and gonadal sex steroids are secreted in a pulsatile fashion. As the peripheral plasma concentrations of GnRH are too low for the existing assay systems, the pattern of pulsatile release of gonadotropins is often utilized for the indirect estimation of hypothalamic GnRH activity. In addition, the long-term pulsatile administration of exogenous GnRH in selected states of GnRH deficiency provides important information on the regulation of the HPG axis. Because of the limits of each approach, both investigational tools should be used complementary for the study of GnRH role in the control of pituitary and gonadal function. This article reviews recent information on GnRH physiology acquired with the use of these methods.

Animals↗
PubMed1981

Hormone levels in methadone-treated drug addicts.

To test the effect of methadone on hormone release in man, plasma levels of luteinizing hormone (LH), follicle-stimulating hormone (FSH), 17-beta-estradiol (E2), estrone (E1), progesterone (P), testosterone (T), dehydrotestosterone (DHT), androstenedione (A), dehydroepiandrosterone sulphate (DS), and prolactin (PRL) have been evaluated in 25 male subjects in treatment wit 30 mg/day methadone per os for at least two months after a minimum of one year of heroin addiction. All subjects had a history of sexual difficulties. The levels of E1, E2, P and LH were always within normal values whereas FSH showed lower values than normal and A, DS and PRL noticeably increased in many subjects. Modest variations were noted for T and DHT. These data seem to indicate that methadone abuse affects the hypophysis, the testiculum and the adrenal cortex. More details will probably be obtained when the variations in hormone rates and opiate serum concentrations are checked at a later date.

Adolescent↗