LH and FSH subunit mRNA concentrations during the progesterone-induced gonadotropin surge in ovariectomized estrogen-primed immature rats

A meta-analysis of efficacy on dexamethasone and clomiphene in the treatment of polycystic ovary syndrome patients

OBJECTIVE

Polycystic ovary syndrome (PCOS) is an endocrine gynecological disease affecting many women of reproductive age. Clomiphene is the first-line treatment for PCOS patients, but most individuals may be resistant to it. This study aims to assess the efficacy of dexamethasone and clomiphene in the treatment of PCOS patients, and to provide a theoretical basis for clinicians to study and treat PCOS.

METHODS

Chinese and English databases including PubMed, Embase, Cochrane Library, China National Knowledge Infrastructure (CNKI), WanFang Medical Network, and VIP Information Chinese Journal Service Platform (VIP) were searched from the inception to January 2023. Review Manager and Stata software were used for meta- analysis. The risk of bias of eligible studies were assessed using Cochrane's risk of bias tool. Publication bias was assessed by funnel plots, Begg's and Egger's tests.

RESULTS

A total of 12 literatures were finally included, with a total of 1270 PCOS patients. Compared with the control group, dexamethasone combined with clomiphene could significantly improve pregnancy (RR = 1.71, P < 0.00001), ovulation (RR = 1.30, P < 0.00001), luteinizing hormone level (SMD = -0.94, P < 0.00001), estradiol level (SMD = 0.99, P = 0.05), progesterone level (SMD = 5.08, P = 0.002) and testosterone level (SMD = -1.59, P < 0.00001). However, there were no significant effects on ovulation-stimulating hormone level (SMD = 0.15, P = 0.37), adverse reactions (RR = 1.30, P = 0.30), dizziness (RR = 1.50, P = 0.45), and vomiting (RR = 1.67, P = 0.48).

CONCLUSION

The treatment of dexamethasone combined with clomiphene is helpful to improve the ovulation and pregnancy rate in patients with PCOS, and improve the hormone levels of patients.

Ovulation induction with letrozole and dexamethasone in infertile patients with letrozole-resistant polycystic ovary syndrome

PURPOSE

To assess efficacy of adjuvant dexamethasone during letrozole cycles for ovulation induction (OI) in women with letrozole-resistant polycystic ovary syndrome (PCOS).

METHODS

We retrospectively evaluated 42 cycles of OI from 28 infertile women with letrozole-resistant PCOS between September 2019 and November 2022. Letrozole was initiated on cycle day 3 for 5 days and increased via a stair-step approach to 7.5 mg as indicated. Patients were deemed letrozole-resistant if no dominant follicle was identified on transvaginal ultrasound following this dose. Resistant patients then received 5 additional days of letrozole 7.5 mg with low-dose dexamethasone 0.5 mg for 7 days and had a repeat ultrasound. The primary outcome was ovulation rate determined by the presence of a dominant follicle on ultrasound. Secondary outcomes included endometrial thickness, number of measurable follicles, and pregnancy outcomes among responders.

RESULTS

Twenty-two of 28 (79%) letrozole-resistant PCOS patients had evidence of ovulation after the addition of dexamethasone in 35 out of 42 (83%) cycles. Clinical pregnancy occurred in 20% of ovulatory cycles with a cumulative rate of 32%. All clinical pregnancies resulted in a live birth. Patients who responded to adjuvant dexamethasone were more likely to have a shorter duration of infertility; however, there were no differences in other demographics, serum androgens including DHEA-S, or pretreatment glycemic status.

CONCLUSION

Adding dexamethasone to letrozole increased ovulation rates in letrozole-resistant PCOS patients undergoing OI with similar pregnancy outcomes to prior studies. The addition of dexamethasone is an effective, inexpensive, and safe option for PCOS patients otherwise at risk for cycle cancelation.

Hirsutism, virilism, polycystic ovarian disease, and the steroid-gonadotropin-feedback system: a career retrospective

This career retrospective describes how the initial work on the mechanism of hormone action provided the tools for the study of hirsutism, virilism, and polycystic ovarian disease. After excessive ovarian and or adrenal androgen secretion in polycystic ovarian disease had been established, the question whether the disease was genetic or acquired, methods to manage hirsutism and methods for the induction of ovulation were addressed. Recognizing that steroid gonadotropin feedback was an important regulatory factor, initial studies were done on the secretion of LH and FSH in the ovulatory cycle. This was followed by the study of basic mechanisms of steroid-gonadotropin feedback system, using castration and steroid replacement and the events surrounding the natural onset of puberty. Studies in ovariectomized rats showed that progesterone was a pivotal enhancer of estrogen-induced gonadotropin release, thus accounting for the preovulatory gonadotropin surge. The effects of progesterone were manifested by depletion of the occupied estrogen receptors of the anterior pituitary, release of hypothalamic LHRH, and inhibition of enzymes that degrade LHRH. Progesterone also promoted the synthesis of FSH in the pituitary. The 3α,5α-reduced metabolite of progesterone brought about selective LH release and acted using the GABA(A) receptor system. The 5α-reduced metabolite of progesterone brought about selective FSH release; the ability of progesterone to bring about FSH release was dependent on its 5α-reduction. The GnRH neuron does not have steroid receptors; the steroid effect was shown to be mediated through the excitatory amino acid glutamate, which in turn stimulated nitric oxide. These observations led to the replacement of the long-accepted belief that ovarian steroids acted directly on the GnRH neuron by the novel concept that the steroid feedback effect was exerted at the glutamatergic neuron, which in turn regulated the GnRH neuron. The neuroprotective effects of estrogens on brain neurons are of considerable interest.

Use of dexamethasone and clomiphene citrate in the treatment of clomiphene citrate-resistant patients with polycystic ovary syndrome and normal dehydroepiandrosterone sulfate levels: a prospective, double-blind, placebo-controlled trial

OBJECTIVE

To evaluate the effects of short-course administration of dexamethasone (DEX) combined with clomiphene citrate (CC) in CC-resistant patients with polycystic ovary syndrome (PCOS) and normal DHEAS levels.

DESIGN

Prospective, double-blind, placebo-controlled, randomized study.

SETTING

Referral university hospitals.

PATIENT(S)

Two hundred thirty women with PCOS and normal DHEAS who failed to ovulate after a routine protocol of CC.

INTERVENTION(S)

The treatment group received 200 mg of CC from day 5 to day 9 and 2 mg of DEX from day 5 to day 14 of the menstrual cycle. The control group received the same protocol of CC combined with placebo.

MAIN OUTCOME MEASURE(S)

Follicular development, hormonal status, ovulation rate, pregnancy rate.

RESULT(S)

Mean follicular diameters were 18.4124 +/- 2.4314 mm and 13.8585 +/- 2.0722 mm for the treatment and control groups, respectively. Eighty-eight percent of the treatment group and 20% of the control group had evidence of ovulation. The difference in the cumulative pregnancy rate in the treatment and control groups was statistically significant.

CONCLUSION(S)

Hormonal levels, follicular development, and cumulative pregnancy rates improved with the addition of DEX to CC in CC-resistant patients with PCOS and normal DHEAS. This regimen is recommended before any gonadotropin therapy or surgical intervention.

Regulation of the preovulatory gonadotropin surge by endogenous steroids

Estradiol secreted by growing ovarian follicle(s) has been considered classically to be the neural trigger for the preovulatory surge of gonadotropins. The observation that the estradiol-induced gonadotropin surge in ovariectomized rats is of lesser magnitude and duration than that found in the cycling rat at proestrus has resulted in a search for other steroid regulators. Progesterone is a major regulator of the preovulatory gonadotropin surge. It can only act in the presence of an estrogen background, which is necessary for the synthesis of progesterone receptors. In the estrogen-primed ovariectomized rat, progesterone is able to initiate and enhance the gonadotropin surge to the magnitude observed on the day of proestrus and limit it to 1 day. The physiological role of progresterone in the induction of the preovulatory gonadotropin surge has been demonstrated by the attenuation of the progesterone-induced surge and the endogenous proestrus surge by progesterone receptor antagonist RU486 and the progesterone synthesis inhibitor trilostane. The promoter region of the follicle-stimulating hormone (FHS)-beta gene contains multiple progesterone response elements and progesterone brings about FSH release as well. The reduction of progesterone in the 5 alpha-position appears to be important for the regulation of progesterone secretion. Corticosteroids appear to play a significant role in the secondary FSH surge on late proestrus and early estrus.

Neuroendocrine mechanisms underlying the control of gonadotropin secretion by steroids

There is considerable evidence that although estradiol may trigger the preovulatory surge of gonadotropins, progesterone is required for its full magnitude and duration and that glucocorticoids bring about selective follicle-stimulating hormone release. The luteinizing hormone-releasing hormone (LHRH) neuron does not have steroid receptors and is regulated by excitatory amino acid neurotransmission. Steroids do not appear to modulate excitatory amino acid receptors directly but increase release of glutamate in the preoptic area. This may be due to the suppression by steroids of the enzyme glutamatic acid decarboxylase67 that converts glutamate into GABA. NMDA receptors colocalize with nitric oxide synthase-containing neurons that surround the LHRH neurons in the preoptic area and intersect the LHRH fibers in the median eminence. Other potential novel pathways of LHRH release that are currently being explored include carbon monoxide generated by the action of heme oxygenase-2 on heme molecules and bradykinin acting via bradykinin B2 receptors.

Ovulation induction in clomiphene-resistant anovulatory women with normal dehydroepiandrosterone sulfate levels: beneficial effects of the addition of dexamethasone during the follicular phase

OBJECTIVE

To evaluate the effect on ovulation of a 10-day course of dexamethasone (DEX) initiated concurrently with a 5-day course of clomiphene citrate (CC) in CC-resistant patients with normal DHEAS levels.

DESIGN

Retrospective review.

SETTINGS

Patients from the clinical practice of the authors at the Medical College of Georgia, Augusta, Georgia.

PATIENTS

Thirteen oligomenorrheic women with normal DHEAS levels who failed to ovulate on a graduated regimen of CC up to a dose of 150 mg for 5 days.

INTERVENTIONS

Ten-day course of DEX initiated concurrently with a 5-day course of CC; ovulation and pregnancy outcomes recorded.

MAIN OUTCOME MEASURE

Pregnancy.

RESULTS

Eleven of 13 women had evidence of ovulation. Five clinical pregnancies were achieved.

CONCLUSION

These initial data support improvements in follicular development with an overlapping follicular phase regimen of CC and DEX in patients with normal DHEAS levels and a previous poor response.

Diverse modes of action of progesterone and its metabolites

Progesterone and its metabolites have a variety of diverse effects in the brain, uterus, smooth muscle, sperm and the oocyte. The effects include changes in electrophysiological excitability, induction of anesthesia, regulation of gonadotropin secretion, regulation of estrogen receptors, modulation of uterine contractility and induction of acrosome reaction and oocyte maturation. The latency of the effects vary from several seconds to several hours. Thus, it is not surprising that multiple mechanisms of action are involved. The classical mechanism of steroid hormone action of intracellular receptor binding has been supplemented by the possibility of the steroid acting as a transcription factor after the binding of the receptor protein to DNA. Other mechanisms include influence of the steroids on membrane fluidity and acting through other cell signalling systems, membrane receptors and GABA(A) receptors. Of particular interest are multiple mechanisms for the same types of action. For example the effect of progesterone on gonadotropin release is largely exerted via the classical intracellular receptor as well as membrane receptors, whereas 3(alpha),5(alpha)-tetrahydroprogesterone-induced LH release occurs via the GABA(A) receptor system. The inhibition of uterine contractility by progesterone is regulated by progesterone receptors while the action of 3(alpha),5(alpha)-tetrahydroprogesterone on uterine contractility is regulated by GABA(A) receptors. The regulation of the differences in the pattern of progesterone effects on estrogen receptor dynamics in the anterior pituitary and the uterus in the same animal are also of considerable interest.

Glutamate: a major neuroendocrine excitatory signal mediating steroid effects on gonadotropin secretion

The preovulatory gonadotropin surge is induced by progesterone in the cycling female rat or in the ovariectomized estrogen-treated female rat after adequate estrogen-priming activity is present. The source of progesterone under physiological conditions could be the ovary and/or the adrenal. Since the GnRH neuron does not possess estrogen and progesterone receptors, its function is modulated by other CNS neurotransmitters and neurosecretory products. Among these, excitatory amino acids (EAAs) have now been shown to play an important role in the regulation of pulsatile gonadotropin release, induction of puberty and preovulatory and steroid-induced gonadotropin surges. Glutamate, the major endogenous EAA exerts its action through ionotropic and metabotropic receptors. The ionotropic receptors consist of two major classes, the NMDA (N-methyl-D-aspartate) and non-NMDA: kainate and AMPA (DL-alpha-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid) receptors. EAA receptors are found in hypothalamic areas involved with reproduction. While both NMDA and non-NMDA receptors are involved in the regulation of LH secretion, the NMDA receptors appear to be involved with the regulation of puberty and FSH secretion as well. Steroids increase the release rates of glutamate and aspartate in the preoptic area during the gonadotropin surge. Steroids may also regulate the hypothalamic AMPA receptors.

Sphingolipid activator proteins in the neuronal ceroid-lipofuscinoses: an immunological study

The molecular defects underlying neuronal ceroid-lipofuscinoses (NCL) are still unknown. However, more data exist on the composition of the hydrophobic storage material characteristic of NCL. Accumulation of subunit c of the mitochondrial ATP synthase has been shown in most forms of human NCL with the exception of the infantile NCL (INCL) for which we have recently demonstrated storage of sphingolipid activator proteins (SAP). In the present study we raised an antiserum against storage cytosomes purified from INCL brain. Using the anti-INCL antiserum and monospecific SAP antisera, we studied storage material isolated from the brains of patients affected with NCL by Western analysis, and found a 12-kDa protein showing a SAP-like immunoreactivity not only in INCL, but also in all the childhood forms of NCL. Furthermore, using the anti-sap-D antiserum for immunohistochemistry, we observed strong immunoreactivity of the storage cytosomes in all major forms of NCL, and also in tissues of non-neuroectodermal origin. From these data we conclude that the presence of SAP within the storage bodies is a phenomenon common to all major forms of human NCL.

Evidence that progesterone modulates anterior pituitary neuropeptide Y levels during the progesterone-induced gonadotropin surge in the estrogen-primed intact immature female rat

In a previous study we reported that in vivo estrogen-priming alone, without subsequent progesterone-treatment, was sufficient to maximize NPY potentiation of gonadotropin hormone-releasing hormone responsiveness exhibited in vitro by the rat anterior pituitary. This observation suggests that the necessity, as reported by others, for both estrogen-priming and progesterone-treatment to maximize NPY potentiation of GnRH responsiveness in vivo may be due to progesterone acting primarily at the hypothalamus. Consequently, the current study was performed to determine whether progesterone facilitates gonadotropin secretion in vivo by acting to stimulate hypothalamic synthesis of NPY and the subsequent elevation of anterior pituitary tissue levels of NPY. Intact immature female rats were injected with estradiol at 1700 h on days 27 and 28. On day 29 at 0900 h, the animals received an injection of progesterone (2 mg/kg) or vehicle and were subsequently sacrificed at 1200, 1330 and 1500 h. Rats which received only estradiol injections were used as controls. Surge levels of serum LH and FSH were observed at 1330 and 1500 h. Hypothalamic levels of NPY mRNA at 1200 h on day 29 were higher (P < 0.01) in estradiol-primed rats which received progesterone; there was no accompanying statistically significant change in hypothalamic NPY content. NPY content in the anterior pituitary was significantly increased (P < 0.01) at 1200 h on day 29 in estradiol-primed rats which received progesterone; there was no accompanying significant change in anterior pituitary NPY mRNA levels. Hypothalamic GnRH mRNA content was significantly increased (P < 0.01) at 1330 h on day 29 concomitant with the peak of the gonadotropin surge in the estradiol-primed, progesterone-treated rat. The data indicate that progesterone modulates hypothalamic NPY mRNA and anterior pituitary NPY levels as well as GnRH mRNA levels and that modulation of NPY levels in the hypothalamic-pituitary axis occurs prior to modulation of GnRH gene expression. These studies support the hypothesis that in the estrogen-primed rat, progesterone facilitates the induction of the gonadotropin surge by maintaining hypothalamic synthesis of NPY as well as by modulating anterior pituitary NPY tissue levels.

Regulation of anterior pituitary gonadotropin subunit mRNA levels during the preovulatory gonadotropin surge: a physiological role of progesterone in regulating LH-beta and FSH-beta mRNA levels

In a previous study we demonstrated that in the ovariectomized estrogen-primed immature rat, progesterone induced a gonadotropin surge while the gonadotropin mRNA subunit levels were either suppressed or unaltered. This observation has now been confirmed using more frequent time points. Progesterone administered at 0900 h was found to suppress LH-beta mRNA levels at 1300, 1400, and 0800 h the next day, with no subsequent effects at 1000, 1200 or 1600 h. FSH-beta mRNA levels were unaffected by progesterone except for a slight elevation at 1400 h and a suppression at 0800 h. Progesterone was either suppressive or had no effect on alpha mRNA levels. Since elevations in LH-beta and FSH-beta mRNA levels were observed in the cycling rat, the observed differences in the ovariectomized estrogen-primed rat could be due to a higher basal synthesis occurring due to ovariectomy. This was indeed the case because LH-beta and FSH-beta mRNA levels were 3.7- and 42.7-fold higher in such animals as compared to intact estrogen-primed rats. In contrast to the ovariectomized estrogen-primed rats, in intact estrogen-primed rats LH-beta mRNA levels were increased at 1000 h and FSH-beta mRNA levels were increased at 1000, 1200 and 1300 h after the administration of progesterone. In pregnant mare's serum gonadotropin-primed immature rats, LH-beta, FSH-beta and alpha-subunit mRNA levels were significantly elevated at 1800 and 2000 h, paralleling the serum LH and FSH surge. The progesterone antagonist RU486 (0.2 and 1.0 mg) significantly reduced serum LH and FSH levels at 2000 h. The lower dose reduced LH-beta and alpha-subunit mRNA levels at 2000 h and FSH-beta mRNA levels at 1800 h. The higher dose caused an increase in LH-beta mRNA levels at 1200 and 1800 h and a decrease in FSH-beta mRNA levels at 1800 and 2000 h. In conclusion, the present study provides evidence that preovulatory progesterone plays an important role in the increase in FSH-beta mRNA levels as well as the release of LH and FSH during the normal preovulatory gonadotropin surge. This relationship appears to be dependent on the ongoing rate of synthesis because this does not occur in the ovariectomized estrogen-primed rat in which synthesis is at a high basal level. Furthermore, the correlation with FSH appears to be tighter as compared to LH.