Utrogestan as an effective oral alternative for preventing premature luteinizing hormone surges in women undergoing controlled ovarian hyperstimulation for in vitro fertilization

A major cause of cycle cancellation during controlled ovarian hyperstimulation (COH) in women undergoing in vitro fertilization (IVF) is the occurrence of premature luteinizing hormone (LH) surges. Steroidal preparations can modulate the secretion of gonadotropins (Gn); however, few studies using progesterone to inhibit the premature LH surges in COH have been published. The purpose of the study was to evaluate the oral delivery of progesterone soft capsules (Utrogestan) to prevent LH surges from the follicular phase and to compare cycle characteristics as well as to evaluate pregnancy outcomes in subsequent frozen-thawed embryo transfer (FET) cycles. A total of 374 patients were enrolled in this retrospective study, among which 187 patients were simultaneously administered Utrogestan and human menopausal gonadotrophin (hMG) from cycle day 3 until the trigger day. A short protocol including 187 controls with comparable age, body mass index (BMI), infertility duration, and antral follicle count was also used. GnRH agonist (0.1 mg) or hCG (3000 IU) was used for a trigger when the dominant follicles matured. Viable embryos were cryopreserved for later transfer in both groups. The primary outcome was the number of oocytes retrieved. The secondary outcomes included the number of mature oocytes, incidence of premature LH surge, and clinical pregnancy outcomes from FET cycles. Consistent LH suppression was achieved during COH, with a range of 0.07 to 8.9 IU/L, and no premature LH surge was detected. The number of oocytes retrieved in the Utrogestan and hMG protocol was comparable with that in the short protocol (10.92 ± 5.74 vs 10.6 ± 6.22, P > 0.05), and the dose of hMG was higher than that used in the short protocol (1884.22 ± 439.47 IU vs 1446.26 ± 550.48 IU, P < 0.05). No significant between-group difference was observed in the mature oocyte rate (88.88% vs 90.12%), cleavage rate (96.58% vs 96.58%), clinical pregnancy rate (54.27% vs 51.65%), or implantation rate (33.59% vs 34.02%). The study shows that Utrogestan is an effective oral alternative for preventing premature LH surges in women undergoing COH, which will help to establish a convenient user regimen in combination with FET.

Effect of polymeric nanoparticle poly(ethylene glycol)-block-poly(lactic acid) (PEG-b-PLA) on in vitro luteinizing hormone release from anterior pituitary cells of infantile and adult female rats

OBJECTIVES

Polymeric PEG-b-PLA nanoparticles (NPs) were developed for delivery of poorly water-soluble drugs via blood brain barrier into brain parenchyma. We analyzed neuroendocrine disrupting effects of neonatal exposure of female rats to PEG-b-PLA NPs and diethylstilbestrol (DES) on the function of adenohypophyseal gonadotrophs of infantile or adult rats by examining in vitro luteinizing hormone releasing hormone (LHRH)-induced luteinizing hormone (LH) release.

METHODS

Neonatal female Wistar rats were injected intraperitoneally, daily, from postnatal day (PND) 4 to PND7 with PEG-b-PLA NPs (20 mg.kg b.w.(-1)), DES (4 µg.kg b.w.(-1)) or vehicle. At the necropsy day (PND15 in infantile and the first estrus day after PND176 in adult rats), adenohypophyseal cells were isolated by enzymatic digestion, plated in 96-well plates (5×10(4) cells.well(-1)) in serum-supplemented medium and left to recover for 96 h. LHRH (10-7 mol.L(-1)) treatment was performed in serum-free medium for 60 min and LH levels in culture media were determined by radioimmunoassay.

RESULTS

In all experimental groups, in vitro LHRH treatment significantly stimulated LH release from pituitary cells of infantile but not adult female rats. Neonatal DES treatment increased basal LH secretion from cultured pituitary cells of adult but not infantile rats. In both, infantile and adult rats, neonatal treatment with PEG-b-PLA significantly increased basal and LHRH-induced LH release from pituitary cells compared to corresponding controls and DES-treated group.

CONCLUSIONS

Data indicate that neonatal exposure to PEG-b-PLA NPs may alter pituitary LH release, and thereby modify reproductive system development in infantile female rats leading to reproductive dysfunctions in adult age.

Neurokinin B receptor antagonism decreases luteinising hormone pulse frequency and amplitude and delays puberty onset in the female rat

The neural mechanisms controlling puberty onset remain enigmatic. Humans with loss of function mutations in TAC3 or TACR3, the genes encoding neurokinin B (NKB) or its receptor, neurokinin-3 receptor (NK3R), respectively, present with severe congenital gonadotrophin deficiency and pubertal failure. Animal studies have shown ambiguous actions of NKB-NK3R signalling with respect to controlling puberty onset. The present study aimed to determine the role of endogenous NKB-NK3R signalling in the control of pulsatile luteinising hormone (LH) secretion and the timing of puberty onset, and also whether precocious pubertal onset as a result of an obesogenic diet is similarly regulated by this neuropeptide system. Prepubertal female rats, chronically implanted with i.c.v. cannulae, were administered SB222200, a NK3R antagonist, or artificial cerebrospinal fluid via an osmotic mini-pump for 14 days. SB222200 significantly delayed the onset of vaginal opening and first oestrus (as markers of puberty) compared to controls in both normal and high-fat diet fed animals. Additionally, serial blood sampling, via chronic indwelling cardiac catheters, revealed that the increase in LH pulse frequency was delayed and that the LH pulse amplitude was reduced in response to NK3R antagonism, regardless of dietary status. These data suggest that endogenous NKB-NK3R signalling plays a role in controlling the timing of puberty and the associated acceleration of gonadotrophin-releasing hormone pulse generator frequency in the female rat.

Developmental programming: postnatal steroids complete prenatal steroid actions to differentially organize the GnRH surge mechanism and reproductive behavior in female sheep

In female sheep, estradiol (E2) stimulates the preovulatory GnRH/LH surge and receptive behavior, whereas progesterone blocks these effects. Prenatal exposure to testosterone disrupts both the positive feedback action of E2 and sexual behavior although the mechanisms remain unknown. The current study tested the hypothesis that both prenatal and postnatal steroids are required to organize the surge and sex differences in reproductive behavior. Our approach was to characterize the LH surge and mating behavior in prenatally untreated (Control) and testosterone-treated (T) female sheep subsequently exposed to one of three postnatal steroid manipulations: endogenous E2, excess E2 from a chronic implant, or no E2 due to neonatal ovariectomy (OVX). All females were then perfused at the time of the expected surge and brains processed for estrogen receptor and Fos immunoreactivity. None of the T females exposed postnatally to E2 exhibited an E2-induced LH surge, but a surge was produced in five of six T/OVX and all Control females. No surges were produced when progesterone was administered concomitantly with E2. All Control females were mounted by males, but significantly fewer T females were mounted by a male, including the T/OVX females that exhibited LH surges. The percentage of estrogen receptor neurons containing Fos was significantly influenced in a brain region-, developmental stage-, and steroid-specific fashion by testosterone and E2 treatments. These findings support the hypothesis that the feedback controls of the GnRH surge are sensitive to programming by prenatal and postnatal steroids in a precocial species.

Nimodipine, a calcium channel blocker, delays the spontaneous LH surge in women with regular menstrual cycles: a prospective pilot study

BACKGROUND

Currently GnRH analogue injections are used to prevent premature LH surges in women undergoing assisted reproductive technology. This was a pilot study to determine the safety and effectiveness of nimodipine, an oral calcium channel blocker, to delay the mid-cycle spontaneous LH surge in women with regular menstrual cycles.

METHODS

Eight women with regular menstrual cycles self-monitored three consecutive cycles for the day of an LH surge by daily urine assay. The first and third cycles were observatory. In the second cycle, subjects took nimodipine 60 mg by mouth three times daily for four days, starting two days prior to the expected LH surge day based on cycle one.

RESULTS

The LH surge day in cycle 2 (nimodipine) was significantly delayed in comparison to both observatory cycle 1 (15.5+/-3.4 vs 14.0+/-2.8 days; p=0.033) and cycle 3 (15.1+/-3.5 vs 13.1+/-2.4 days; p=0.044). There was no difference in the LH surge day between the two observatory cycles (13.4+/-2.4 vs 13.1+/-2.4 days; p=0.457). Three patients experienced a mild headache.

CONCLUSIONS

There was a statistically significant delay in the spontaneous LH surge day in the treatment cycle in comparison to both observatory cycles. Nimopidine should be further investigated as an oral alternative to delay a spontaneous LH surge.

The effect of valproate (VPA) treatment on inositol phosphates (IPs) accumulation in non-stimulated and GnRH-treated female rat anterior pituitary cells in vitro

OBJECTIVE

Mechanism(s) responsible for VPA-induced effects on reproductive axis activity are not fully recognized. Previously we reported that VPA suppressed only GnRH-stimulated but not the basal LH release from rat anterior pituitary (AP) cells in vitro. Since the inhibitory effect of VPA was exerted only in GnRH-activated cells, potential VPA impact on GnRH-R-coupled IP3/PKC signaling could not be excluded. In this study the effect of VPA on IPs synthesis in non-stimulated and GnRH-treated rat AP cells was examined.

MATERIAL AND METHODS

In the first experiment 5 × 105 cells/ml were incubated for 3h with VPA (10 nM-10 μM), PMA (100 nM), GnRH (100 nM), PMA (100 nM) + VPA (10 nM-10 μM), GnRH (100 nM) + VPA (10 nM-10 μM). In the second experiment cells were preincubated for 24h with 1μCi myo-[23 H]-inositol, then for 30 min with 10 mM LiCl and finally for 3hr with GnRH (100 nM) VPA (1 μM, 10 μM), GnRH (100 nM) + VPA (1 μM, 10 μM). LH concentration was measured by RIA and intracellular IPs accumulation by ion-exchange chromatography analysis.

RESULTS

VPA diminished GnRH-stimulated LH release without affecting PMA-induced LH release at any dose tested. Moreover, VPA-induced increase of IPs accumulation occurred in both non-stimulated and GnRH-treated cells and intensity of cellular response was similar in both groups.

CONCLUSION

VPA affects IP3/PKC pathway activity through its up-regulatory effect on IPs synthesis in AP cells. VPA-induced inhibition of GnRH-stimulated LH release from gonadotrope cells appears to be the result of still unrecognized cellular mechanism.

Effects of alarin on food intake, body weight and luteinizing hormone secretion in male mice

Alarin is a member of the galanin family of neuropeptides that includes galanin and galanin-like peptide (GALP). Alarin is an alternate transcript of the GALP gene and is expressed in the brain and periphery. Recently, it was shown in male rats that alarin is an orexigenic peptide that also regulates reproductive hormone secretion. We hypothesized that alarin would also have similar central effects on feeding and luteinizing hormone (LH) secretion in mice as observed in rats. To test this hypothesis, we treated male mice with alarin intracerebroventricularly (i.c.v.) and measured its effects on food intake, body weight, body temperature, LH secretion, and Fos induction. We observed that i.c.v. injection of 1.0 nmol alarin significantly increased immediate food intake (p<0.01) from 30 to 120 min post-injection and relative body weight (p<0.05) after 24 h. Alarin had no effect on body temperature compared to controls. Alarin increased LH levels in male mice, an effect that was dependent on gonadotropin-Releasing-Hormone (GnRH) signaling. Furthermore, alarin-stimulated Fos immunoreactivity was observed in diencephalic nuclei, including the hypothalamic dorsomedial nucleus and the bed nucleus of the stria terminalis. Our studies demonstrated that alarin, like other members of the galanin peptide family, is a neuromediator of food intake and reproductive hormone secretion in male mice.

Effects of GnRH treatment on initiation of pulses of LH, LH release, and subsequent concentrations of progesterone

Progesterone is essential for establishment and maintenance of pregnancy. One proposed method to increase progesterone is administering GnRH at insemination. However, this method has resulted in conflicting results. Therefore, 2 experiments were conducted to evaluate how administering GnRH at insemination affected pulses of luteinizing hormone (LH) and subsequent progesterone. In Experiment 1, cows were allotted to 2 treatments: (1) GnRH (100 microg) given approximately 12h after initiation of estrus (n=5); and (2) Control (n=5). Blood samples were collected at 15-min intervals for 6h at 12 (blood sampling period 1), 26 (blood sampling period 2), 40 (blood sampling period 3), 54 (blood sampling period 4), and 68 (blood sampling period 5) h after onset of estrus. Daily blood samples were collected for 17 d. In Experiment 2, cows were allotted into 2 treatments: GnRH administered 10 to 11h (n=10) or 14 to 15 h (n=10) after onset of estrus. Daily blood samples were collected for 17 d. Cows treated with GnRH tended (P<or=0.075) to have greater LH release during blood sampling period 1, tended (P=0.095) to have fewer pulses during blood sampling period 2, tended (P=0.067) to have greater concentrations of progesterone, and had an earlier (P=0.05) increase in progesterone than control cows. Cows treated with GnRH 10 to 11h after onset of estrus had greater (P=0.01) progesterone and an earlier (P=0.04) increase in progesterone than cows treated 14 to 15 h. In conclusion, timing of GnRH treatment following onset of estrus influenced pulses of LH and subsequent progesterone.

In vitro prolactin but not LH and FSH release is inhibited by compounds in extracts of Agnus castus: direct evidence for a dopaminergic principle by the dopamine receptor assay

Women suffering from premenstrual mastodynia often respond to stimuli of prolactin (Prl) release with a hypersecretion of this hormone. Pharmacological reduction of Prl release by dopamine agonists or treatment with extracts of Agnus castus (AC) improve the clinical situation of patients with such premenstrual symptoms. Extracts of AC contain compounds which inhibit in vivo Prl release in women as well as in vitro from dispersed rat pituitary cells. It is yet unknown whether this inhibitory action of AC is only exerted on Prl release or whether release of other pituitary hormones like LH and FSH is also affected. The effects of AC on LH and FSH release were examined in vitro using rat pituitary cell cultures. To rule out that the Prl-inhibiting properties of AC are at least in part due to a cytotoxic component, pituitary cell cultures were subjected to the MTT test. To assess whether the Prl inhibitory effect of AC preparations is due to compounds acting as dopamine (DA) agonists, we used the corpus striatum membrane DA receptor binding assay. Our results demonstrate for the first time that AC extract contains an active principle that binds to the D2 receptor. Thus, it is very likely that it is this dopaminergic principle which inhibits Prl release in vitro from rat pituitary cells. Furthermore we give evidence for the specificity of action of AC on hormone release, since gonadotropin secretion remained unaffected. The findings of the present study support the therapeutical usefulness of AC extracts for treatment of premenstrual mastodynia which is associated with hypersecretion of Prl. Furthermore, the beneficial effects of AC appear to be due to the inhibition of pituitary Prl release.

Cortistatin and pituitary hormone secretion in rat

Cortistatin (CST), a novel neuropeptide, shows high structural homology and functional resemblance with somatostatin. CST binds with high affinity to all somatostatin receptors, and contrary to somatostatin, is also able to bind with MrgX2 and GH secretagogue receptor of ghrelin (GHS-R1) receptors. The aim of the present investigation was to evaluate in vivo the effect of peripheral administration of cortistatin on pituitary hormone release in comparison with somatostatin (SS) treatment. Adult male rats used in the experiment, were given peripheral injection of cortistatin, somatostatin or vehicle. Blood was withdrawn 60 and 120 minutes thereafter. We found short lasting significant decrease of GH concentration as a result of administration of CST and SS when compared with saline injected controls. Prolactin levels were increased 60 min after cortistatin but not to somatostatin injection. There was no effect of CST on both LH and FSH concentration; however, SS administration influenced gonadotropin secretion. We conclude that cortistatin play a regulatory role in pituitary secretion. Moreover, some differences have been found when compared cortistatin to somatostatin. Thus, when analyzing the mechanism of cortistatin activity it is worth to consider the effect of binding with receptors of somatostatin, specific receptor for CST (MrgX2) and GHS-R.

Insulin modulation of luteinizing hormone secretion in normal female volunteers and lean polycystic ovary syndrome patients

BACKGROUND/AIMS

Endocrine features of polycystic ovary syndrome (PCOS) include altered ovarian steroidogenesis, hyperinsulinemia and abnormal luteinizing hormone (LH) secretion. This study was undertaken to further evaluate the role of insulin to modulate LH secretion in lean PCOS patients with normal insulin sensitivity and normal volunteers.

METHODS

The study was performed in five nonobese patients diagnosed with PCOS on the basis of amenorrhea and a polycystic morphology at ovarian ultrasound, and 5 normal controls in early to mid-follicular phase and matched for weight and age. All subjects were phenotyped, and then admitted for 12 h of frequent (q 10') blood sampling on two separate occasions, once for a baseline study and the other time for a hyperinsulinemic and euglycemic clamp study. LH was measured in samples obtained throughout each admission in order to perform LH pulse analysis.

RESULTS

Baseline LH secretion in PCOS subjects was significantly different from controls: they had higher LH levels, higher LH/FSH ratios as well as a faster LH pulse frequency than normal women. Insulin administration did not affect the pattern of LH secretion of PCOS patients, whereas it significantly increased the LH pulse frequency while decreasing the LH interpulse intervals in the controls.

CONCLUSIONS

These data confirm that an abnormal pattern of LH secretion characteristic of PCOS can be observed in lean patients, and appears independent of peripheral insulin levels. Furthermore, our results in lean controls provide the first direct evidence that peripheral insulin can modulate the activity of hypothalamic gonadotropin-releasing hormone (GnRH) neurons in the human.

Developmental methoxychlor exposure affects multiple reproductive parameters and ovarian folliculogenesis and gene expression in adult rats

Methoxychlor (MXC) is an organochlorine pesticide with estrogenic, anti-estrogenic, and anti-androgenic properties. To investigate whether transient developmental exposure to MXC could cause adult ovarian dysfunction, we exposed Fischer rats to 20 microg/kg/day (low dose; environmentally relevant dose) or 100 mg/kg/day (high dose) MXC between 19 days post coitum and postnatal day 7. Multiple reproductive parameters, serum hormone levels, and ovarian morphology and molecular markers were examined from prepubertal through adult stages. High dose MXC accelerated pubertal onset and first estrus, reduced litter size, and increased irregular cyclicity (P<0.05). MXC reduced superovulatory response to exogenous gonadotropins in prepubertal females (P<0.05). Rats exposed to high dose MXC had increasing irregular estrous cyclicity beginning at 4 months of age, with all animals showing abnormal cycles by 6 months. High dose MXC reduced serum progesterone, but increased luteinizing hormone (LH). Follicular composition analysis revealed an increase in the percentage of preantral and early antral follicles and a reduction in the percentage of corpora lutea in high dose MXC-treated ovaries (P<0.05). Immunohistochemical staining and quantification of the staining intensity showed that estrogen receptor beta was reduced by high dose MXC while anti-Mullerian hormone was upregulated by both low- and high dose MXC in preantral and early antral follicles (P<0.05). High dose MXC significantly reduced LH receptor expression in large antral follicles (P<0.01), and down-regulated cytochrome P450 side-chain cleavage. These results demonstrated that developmental MXC exposure results in reduced ovulation and fertility and premature aging, possibly by altering ovarian gene expression and folliculogenesis.

Effect of subluteal concentrations of progesterone on luteinizing hormone and ovulation in lactating dairy cows

Two experiments were conducted to determine if administration of progesterone within a low, subluteal range (0.1-1.0 ng/mL) blocks the luteinizing hormone (LH) surge (experiments 1 and 2) and ovulation (experiment 2) in lactating dairy cows. In experiment 1, progesterone was administered to cycling, lactating dairy cows during the luteal phase of the estrous cycle using a controlled internal drug release (CIDR) device. CIDRs were pre-incubated in other cows for either 0 (CIDR-0), 14 (CIDR-14) or 28 days (CIDR-28). One group of cows received no CIDRs and served as controls. One day after CIDR insertion, luteolysis was induced by two injections of prostaglandin (PG) F(2alpha) (25 mg) at 12 h intervals. Two days after the first injection, estradiol cypionate (ECP; 3 mg) was injected to induce a LH surge. Concentrations of progesterone after luteolysis were 0.11, 0.45, 0.78 and 1.20 ng/mL for cows treated with no CIDR, CIDR-28, CIDR-14, and CIDR-0, respectively. LH surges were detected in 4/4 controls, 4/5 CIDR-28, 2/5 CIDR-14 and 0/5 CIDR-0 cows following ECP. In experiment 2, progesterone was administered to cycling, lactating, Holstein cows during the luteal phase of the estrous cycle as in experiment 1. Luteolysis was induced as in experiment 1. The occurrence of an endogenous LH surge and ovulation were monitored for 7 days. Concentrations of progesterone after luteolysis were 0.13, 0.30, 0.70 and 1.20 ng/mL for cows treated with no CIDR, CIDR-28, CIDR-14 and CIDR-0, respectively. LH surges and ovulation were detected in 5/5 controls, 3/7 CIDR-28, 0/5 CIDR-14 and 0/5 CIDR-0 cows. It was concluded that low concentrations of progesterone can reduce the ability of either endogenous or exogenous estradiol to induce a preovulatory surge of LH and ovulation.

Alteration of fertility endpoints in adult male F-344 rats by subchronic exposure to inhaled benzo(a)pyrene

The objective of this study was to evaluate the reproductive risk associated with exposure of adult male Fisher-344 rats to inhaled benzo(a)pyrene (BaP). Rats were assigned randomly to a treatment or control group. Treatment consisted of sub-chronic exposure of rats via inhalation to 75microgBaP/m(3), 4h daily for 60 days, while control animals were unexposed (UNC). Blood samples were collected immediately after the cessation of exposures (time 0) and subsequently at 24, 48, and 72h, to assess the effect of bioavailable BaP on plasma testosterone and luteinizing hormone (LH) concentrations. Rats were sacrificed after the last blood collection. Testes were harvested, weighed and prepared for histology and morphometric analysis, and cauda epididymides were isolated for the determination of progressive motility and density of stored spermatozoa. BaP exposure reduced testis weight compared with UNC (mean+/-SE; 2.01+/-0.11 versus 3.04+/-0.16g; P<0.025), and caused significant reductions in the components of the steroidogenic and spermatogenic compartments of the testis. Progressive motility and mean density of stored spermatozoa were reduced (P<0.05). Plasma testosterone concentrations were decreased by two-thirds in BaP-exposed rats throughout the time periods studied compared with those of their UNC counterparts (P<0.05), concomitant with increased concentrations of LH in BaP-exposed rats (P<0.05). These data suggest that sub-chronic exposure to inhaled BaP contribute to reduced testicular and epididymal function in exposed rats.

Prenatal testosterone treatment alters LH and testosterone responsiveness to GnRH agonist in male sheep

Although evidence is accumulating that prenatal testosterone (T) compromises reproductive function in the female, the effects of excess T in utero on the postnatal development of male reproductive function has not been studied. The aim of this study was to assess the influence of prenatal T excess on age-related changes in pituitary and gonadal responsiveness to GnRH in the male sheep. We used the GnRH agonist, leuprolide (10 microg/kg), as a pharmacologic challenge at 5, 10, 20 and 30 weeks of age. These time points correspond to early and late juvenile periods and the prepubertal and postpubertal periods of sexual development, respectively. LH and T were measured in blood samples collected before and after GnRH agonist administration. The area under the response curve (AUC) of LH increased progressively in both controls and prenatal T-treated males from 5 to 20 weeks of age (P<0.01). The LH responses in prenatal T-treated males were lower at 20 and 30 weeks of age compared to controls (P<0.05). AUC-T increased progressively in control males from 5 through 30 weeks of age and prenatal T-treated males from 5 to 20 weeks of age. The T response in prenatal T-treated males was higher at 20 weeks compared to controls of same age but similar to controls and prenatal T-treated males at 30 weeks of age (P <0.05). Our findings suggest that prenatal T treatment advances the developmental trajectory of gonadal responsiveness to GnRH in male offspring.

The use of metformin as first line treatment in polycystic ovary syndrome

This study evaluated the use of metformin as first line treatment for patients with polycystic ovary syndrome. A retrospective review of patients' files diagnosed with PCOS over 16 months in Department of obstetrics and gynaecology of a Regional hospital. The outcome was the response to metformin treatment regardless of the main complaint. Treatment response was measured by change in LH/FSH ratio, fasting insulin, testosterone, day 21 progesterone and/or pregnancy. A day 21 progesterone greater than 25.5 nmol/l and/or pregnancy were the parameter of ovulation. Thirty-four patients were diagnosed with PCOS. Twenty-five complained of infertility (14 primary and 11 secondary), six patients had oligomenorrhoea or amenorrhoea and three presented with hirsutism. Seventeen patients received metformin as first line treatment. Eight received it with other treatment (5 clomiphene citrate and 3 ant androgens). Nine patients did not receive metformin. This study justifies the use of metformin as an appropriate first line treatment for PCOS.

Effects of chronic genistein treatment in mammary gland, uterus, and vagina

BACKGROUND

The isoflavone genistein (GEN) is found in soy (Glycine max) and red clover (Trifolium pratense). The estrogenic activity of GEN is known, and it is widely advertised as a phytoestrogen useful in alleviating climacteric complaints and other postmenopausal disorders. Knowledge of effects of long-term administration of GEN in laboratory animals is scarce, and effects in the uterus and mammary gland after long-term administration have not been studied. The uterus and mammary gland are known to be negatively influenced by estrogens used in hormone therapy.

OBJECTIVES

We administered two doses of GEN [mean daily uptake 5.4 (low) or 54 mg/kg (high) body weight (bw)] orally over a period of 3 months to ovariectomized (ovx) rats and compared the effects with a treatment with two doses of 17beta-estradiol [E(2); 0.17 (low) or 0.7 mg/kg bw (high)]. Mammary glands, vaginae, and uteri were investigated morphologically and immunohistochemically. We quantified the expression of proliferating cell nuclear antigen (PCNA) and progesterone receptor (PR) in the mammary gland.

RESULTS

In rats treated with either of the E(2) doses or the high GEN dose, we found increased uterine weight, and histologic analysis showed estrogen-induced features in the uteri. In vaginae, either E(2) dose or GEN high induced hyperplastic epithelium compared with the atrophic controls. In the mammary gland, E(2) (either dose) or GEN increased proliferation and PR expression. Serum levels of luteinizing hormone were decreased by E(2) (both doses) but not by GEN.

CONCLUSIONS

In summary, E(2) and GEN share many effects in the studied organs, particularly in the vagina, uterus, and mammary gland but not in the hypothalamo/pituitary unit.

Extension of GnRH agonist through the luteal phase to improve the outcome of intracytoplasmic sperm injection

OBJECTIVE

To investigate the effect of continuous administration of gonadotropin-releasing hormone agonist (GnRHa) during the luteal phase in an intracytoplasmic sperm injection program.

STUDY DESIGN

One hundred eighty-one women underwent a down-regulation protocol of GnRHa administered from the 21st day of the preceding cycle. Patients were randomized at initiation of stimulation by a computer-generated list. Group 1 patients (n = 90) were continuously administered GnRHa for 12 days after embryo transfer, while in group 2 patients GnRHa was stopped on the day of human chorionic gonadotropin administration.

RESULTS

Demographic parameters, infertility etiologies, number of gonadotropin ampules used, number of mature oocytes recovered, rates of testicular sperm usage, number of embryos transferred, and cycle and transfer cancellation rates were similar in both groups. Clinical pregnancy rates, implantation rates and live birth rates did not show a significant difference.

CONCLUSION

Extending GnRHa treatment through the luteal phase appeared not to have a significant impact on pregnancy or implantation rates in intracytoplasmic sperm injection cycles.

Dietary daidzein and puerarin do not affect pituitary LH expression but exert uterotropic effects in ovariectomized rats

OBJECTIVE

To investigate the potency of LH suppression, as an indirect measure of alleviation of postmenopausal vasomotor symptoms, as well as the uterotropic effects of two isoflavones: daidzein and puerarin in an ovariectomized (ovx) rat model and compare them with the effects of 17beta-estradiol benzoate (E2B).

DESIGN

Eighty female Sprague-Dawley rats were ovx and divided into six different treatment groups and one control group (11-12 animals per group). Daidzein, puerarin and E2B were added to the soy free rodent chow in low and high doses (250 mg and 1000 mg per kg, 600 mg and 3000 mg per kg and 4.3 mg and 17.3 mg per kg, respectively). After 3 months of treatment, animals were sacrificed and using real time RT-PCR, pituitary LHbeta and uterine IGF-1, PR and C3 mRNA levels were measured. Additionally serum LH levels were measured in a radioimmunoassay.

RESULTS

Both of our tested isoflavones at low and high doses had no effect on the expression of the pituitary LH at the mRNA and protein level. Only E2B at both doses significantly decreased pituitary LHbeta gene expression and serum LH levels. Daidzein and puerarin at high dose increased significantly uterine weights. Uterine IGF-1 gene expression was only upregulated in puerarin high group. Uterine PR mRNA levels were higher in animals fed with low dose daidzein and high dose puerarin. Uterine C3 gene expression was upregulated in animals fed with daidzein and puerarin at high doses. Although statistically significant, all these effects were however very discrete compared to those of E2B at low and high doses.

CONCLUSION

We speculate that due to the lack of LH suppressing effects in our model, it is very unlikely for daidzein and puerarin to alleviate vasomotor symptoms in postmenopausal women. In contrast, due to their uterotropic effects, high dose consumption of commercially available preparations containing daidzein or puerarin may expose women with an intact uterus to the risk of endometrial hyperplasia.

Antifertility activity of the methanolic leaf extract of Cissampelos pareira in female albino mice

meenakshi Cissampelos pareira Linn. is one of the folk medicinal plants commonly used as antifertility agent in some places of India. The aim of the present study was to evaluate the validity of the antifertility effect of the leaf extract. Cissampelos pareira leaf extract, when administered orally, altered the estrous cycle pattern in female mice, prolonged the length of estrous cycle with significant increase in the duration of diestrus stage and reduced significantly the number of litters in albino mice. The analysis of the principal hormones involved in estrous cycle regulation showed that the plant extract altered gonadotropin release (LH, FSH and prolactin) and estradiol secretion. The results indicated the antifertility effect of Cissampelos pareira leaf extract in female albino mice. The oral LD50 of the extract was found to be 7.3 g/kg in mice.

The effects of GABA agonists on glutamic acid decarboxylase, GABA-transaminase, activin, salmon gonadotrophin-releasing hormone and tyrosine hydroxylase mRNA in the goldfish (Carassius auratus) neuroendocrine brain

GABA plays a pivotal role in reproduction by regulating luteinising hormone (LH) release from the anterior pituitary. Current evidence indicates that there is a prominent stimulatory effect of GABA on LH release in teleost fish which results from enhanced gonadotrophin-releasing hormone (GnRH) release and decreased dopamine turnover in the brain and pituitary. We hypothesised that there may be additional mechanisms underlying LH release in goldfish and investigated the relative mRNA levels of GABA synthesising enzymes (GAD65 and GAD67), degrading enzyme (GABA-T), activin betaa and betab, salmon GnRH (sGnRH), and tyrosine hydroxylase (TH) with the real-time reverse transcriptase-polymerase chain reaction after GABA agonist treatment. Sexually regressed female goldfish were i.p. injected with either the GABA(A) agonist muscimol (1 microg/g body weight) or the GABA(B) agonist baclofen (10 microg/g body weight). Both agonists significantly increased serum LH after 6 h. Muscimol decreased GAD65 (approximately ten-fold), GABA-T (approximately 15-fold) and TH (approximately three-fold) mRNA in the telencephalon. Baclofen significantly reduced GAD67 (approximately two-fold) and GABA-T (approximately two-fold) mRNA levels in the hypothalamus. Activin betaa, but not activin betab, steady-state mRNA was increased approximately three- to four-fold in both the hypothalamus and telencephalon after baclofen treatment. There was no change in sGnRH mRNA levels in either tissue after GABA agonist treatment. We show that the GABA(A) and GABA(B) receptor agonists have differing and rapid effects on gene transcription in the goldfish neuroendocrine brain and, by affecting specific targets, we identify putative genomic mechanisms underlying GABA-stimulated LH release in fish.

Pharmacokinetics and systemic endocrine effects of the phyto-oestrogen 8-prenylnaringenin after single oral doses to postmenopausal women

AIMS

Pre-clinical data suggest that the racemic phyto-oestrogen 8-prenylnaringenin (8-PN) may have beneficial effects in postmenopausal women and may become an alternative to classical hormone replacement therapy (HRT) treatment regimes. The aim of this study was to investigate the pharmacokinetics, endocrine effects and tolerability of chemically synthesized 8-PN in postmenopausal women.

METHODS

The study was performed using a randomized, double-blind, placebo-controlled, dose-escalation design with three groups of eight healthy postmenopausal women. In each group six subjects received 8-PN and two subjects placebo. 8-PN was given orally in doses of 50, 250 or 750 mg. Drug concentrations in serum, urine and faeces were measured up to 48 h and follicle-stimulating hormone/luteinizing hormone (LH) concentrations up to 24 h.

RESULTS

All treatments were well tolerated and associated with a low incidence of (drug unrelated) adverse events. Serum concentrations of free 8-PN showed rapid drug absorption and secondary peaks suggestive of marked enterohepatic recirculation. Independent of the treatment group, approximately 30% of the dose was recovered in excreta as free compound or conjugates over the 48-h observation period. The first C(max) and AUC(0-48 h) showed dose linearity with ratios of 1 : 4.5 : 13.6 (C(max)) and 1 : 5.2 : 17.1 (AUC). The750- mg dose decreased LH concentrations by 16.7% (95% confidence interval 0.5, 30.2).

CONCLUSION

Single oral doses of up to 750 mg 8-PN were well tolerated by postmenopausal women. The pharmacokinetic profile of 8-PN was characterized by rapid and probably complete enteral absorption, high metabolic stability, pronounced enterohepatic recirculation and tight dose linearity. The decrease in LH serum concentrations found after the highest dose demonstrates the ability of 8-PN to exert systemic endocrine effects in postmenopausal women.

[Change of pulsatile release and luteinizing hormone response to naloxone related to testicle damage]

OBJECTIVE

To compare the pulsatile release of LH, the tone of endogenous opioids and the mass of LH secreted after a naloxone infusion in healthy subjects and patients with normogonadotropic oligospermia (NO) in a model of progressive testicular damage.

PATIENTS AND METHODS

Pulsatile secretion of LH was analyzed in a period of 8 hours in a group of healthy subjects (group 3, n=5), in patients with NO and FSH/LH ratio <1.6 (group 1, n=5) and in patients with NO and FSH/LH ratio >1.6 (group 2, n=5). The area under the curve of LH response after naloxone infusion was also calculated.

RESULTS

Free serum testosterone concentration was lower (p < 0.01) and estradiol concentration higher in patients with NO than control subjects (1 vs. 3: p = 0.01; 2 vs. 3: p = 0.001). Frequency of pulses in group 1 was 3.33 +/- 0.57/8 h, in group 2: 4 +/- 1/8 h; and in group 3: 2.66 - 0.57/8 h (2 vs. 3 p < 0.01; 2 vs. 1 p = 0.05). The area under the curve after naloxone infusion was 19,300.44 +/- 11,403.31 in group 1, 5696.09 +/- 1753.44 in group 2; and 3080.97 +/- 1159.78 in group 3 (1 vs. 3 Anova p = 0.01).

CONCLUSIONS

The data indicate that patients with NO have a subclinical pantesticular failure and that the opioid tone is increased at the initial phase of testicular dysfunction, but it decreases at more advanced stages of testicular damage.

Effect of single administration of levonorgestrel on the menstrual cycle

BACKGROUND

Levonorgestrel (LNG) 1.5 mg administered within 72 h of unprotected coitus is an established method of emergency contraception. Currently, there is some, although incomplete, knowledge about the mechanism of action.

METHODS

We administered 1.5 mg LNG peri-ovulatory to determine the effects on serum gonadotrophins, estradiol and progesterone levels. Fourteen women were studied in a pretreatment and treatment cycle; eight women (Group A) took LNG 3 days before the expected day of ovulation, while 6 (Group B) took LNG a day before the expected day of ovulation.

RESULTS

The women in Group A had a significant delay in their LH peak and onset of the next menses compared with their pretreatment cycles (26.4 vs. 39.1 days, p<.05). Those in Group B had no significant changes in the endocrine parameters but there was a significant shortening of the mean cycle length in comparison with their pretreatment cycles (25.1 vs. 20.2 days).

CONCLUSION

Levonorgestrel 1.5 mg acts as an emergency contraception by delaying the LH surge and interfering with ovulation. It may also disrupt corpus luteum formation causing premature luteinization of unruptured follicles.

Study of enteral versus parenteral application of the gonadotropin releasing hormone agonist Gonadorelin[6-D-Phe] (D-Phe6-LHRH) on LH secretion in Goettinger miniature pigs

With respect to the assessment of residue situation and as a part of preclinical trials to determine the biological activities of potential gonadotropin releasing hormone (GnRH) residues in porcine organisms the GnRH agonist Gonadorelin[6-D-Phe] (D-Phe(6)-LHRH) was administered either enterally or intramuscularly (i.m.) to female Goettinger miniature pigs in order to evaluate the GnRH-induced luteinizing hormone (LH) surge. Gilts received an (i) enteral application of 10 mg D-Phe(6)-LHRH via a probang (enteral group, n=7), (ii) i.m. injection of 0.1 mg D-Phe(6)-LHRH (parenteral group, n=5), or (iii) saline injection (control group, n=4). The GnRH and saline applications were repeated every second day with up to seven repetitions. Blood samples were collected via previously fitted jugular catheters immediately before injections, over an 8 h period in 1 h intervals beginning 2 h after injections, and at 24, 26, 28 and 30 h after applications. Enteral application of D-Phe(6)-LHRH induced an LH surge in 23 of 30 treatments. All gilts in the parenteral group exhibited LH release after each D-Phe(6)-LHRH application (P<0.05), whereas no LH surges were observed after saline injection in the control group. A significant (P<0.05) LH rise to mean maximum LH concentrations of 3.25 +/- 0.43 and 3.05 +/- 0.26 ng/ml occurred in both the enteral and parenteral groups, but there was no difference in the time interval after GnRH (2.6 +/- 0.3 vs. 2.3 +/- 0.3 h) and the mean duration of LH peak (6.5 +/- 0.4 and 6.8 +/- 0.3 h) between the treatment groups. In conclusion, (i) enteral application of 10 mg D-Phe(6)-LHRH induced LH release in a physiological range from the pituitary of female minipigs, and (ii) neither an accumulative effect nor a cumulative LH response were found after repeated GnRH application. Furthermore, (iii) in regard to consumer protection and gonadotropin secretion, D-Phe(6)-LHRH residues can be excluded from having long-term effects.