Hyperandrogenism and Polycystic ovary syndrome: Effects in pregnancy and offspring development.

Polycystic ovary syndrome (PCOS) is one of the major endocrine disorders affecting women of reproductive age. Its etiology remains unclear. It is suggested that environmental factors, and particularly the intrauterine environment, play key roles in PCOS development. Besides the role of androgens in PCOS pathogenesis, exposure to endocrine disruptors, as is Bisphenol A, could also contribute to its development. Although PCOS is considered one of the leading causes of ovarian infertility, many PCOS patients can get pregnant. Some of them by natural conception and others by assisted reproductive technique treatments. As hyperandrogenism (one of PCOS main features) affects ovarian and uterine functions, PCOS women, despite reaching pregnancy, could present high-risk pregnancies, including implantation failure, an increased risk of gestational diabetes, preeclampsia, and preterm birth. Moreover, hyperandrogenism may also be maintained in these women during pregnancy. Therefore, as an altered uterine milieu, including hormonal imbalance, could affect the developing organisms, monitoring these patients throughout pregnancy and their offspring development is highly relevant. The present review focuses on the impact of androgenism and PCOS on fertility issues and pregnancy-related outcomes and offspring development. The evidence suggests that the increased risk of pregnancy complications and adverse offspring outcomes of PCOS women would be due to the factors involved in the syndrome pathogenesis and the related co-morbidities. A better understanding of the involved mechanisms is still needed and could contribute to a better management of these women and their offspring. This article is categorized under: Reproductive System Diseases > Molecular and Cellular Physiology Reproductive System Diseases > Environmental Factors.

Inflammation and reproductive function in women with polycystic ovary syndrome†.

Polycystic ovary syndrome (PCOS) is one of the most frequent endocrinopathies, affecting 5-10% of women of reproductive age, and is characterized by the presence of ovarian cysts, oligo, or anovulation, and clinical or biochemical hyperandrogenism. Metabolic abnormalities such as hyperinsulinemia, insulin resistance, cardiovascular complications, dyslipidemia, and obesity are frequently present in PCOS women. Several key pathogenic pathways overlap between these metabolic abnormalities, notably chronic inflammation. The observation that this mechanism was shared led to the hypothesis that a chronic inflammatory state could contribute to the pathogenesis of PCOS. Moreover, while physiological inflammation is an essential feature of reproductive events such as ovulation, menstruation, implantation, and labor at term, the establishment of chronic inflammation may be a pivotal feature of the observed reproductive dysfunctions in PCOS women. Taken together, the present work aims to review the available evidence about inflammatory mediators and related mechanisms in women with PCOS, with an emphasis on reproductive function.

Increased chemerin serum levels in hyperandrogenic and normoandrogenic women from Argentina with polycystic ovary syndrome.

AIM: To assess serum chemerin levels and investigate the association of chemerin with the hyperandrogenic and normoandrogenic phenotypes of Polycystic Ovary Syndrome (PCOS) and with the metabolic status of the analyzed population. MATERIAL AND METHODS: A cross-sectional study was conducted on 106 women with PCOS and 60 healthy controls from Argentina. Patients were classified as showing a hyperandrogenic or normoandrogenic phenotype. Participants underwent anthropometric and clinical evaluation and markers of cardiovascular risk, insulin resistance, metabolic syndrome (MS), and serum chemerin levels were assessed. RESULTS: PCOS patients showed increased levels of chemerin. In adjusted models for age and body mass index (BMI), chemerin was associated with markers of metabolic status. The analysis of chemerin levels considering the cutoff values of BMI, homeostatic model of insulin sensitivity (HOMA-IR) and TG/HDL marker showed that PCOS patients always presented higher levels of chemerin than controls. PCOS group showed increased chemerin levels independently of the presence of MS. CONCLUSION: PCOS patients always showed increased levels of chemerin independently of their phenotype and presence of overweight, as well as higher levels of chemerin than controls when considering the cutoff values of HOMA-IR and TG/HDL. Therefore, argentine women with PCOS display increased chemerin levels independently of their metabolic or androgenic status.

Prenatal androgen excess alters the uterine peroxisome proliferator-activated receptor (PPAR) system.

It is known that androgen excess induces changes in fetal programming that affect several physiological pathways. Peroxisome proliferator-activated receptors (PPARs) α, δ and γ are key mediators of female reproductive functions, in particular in uterine tissues. Thus, we aimed to study the effect of prenatal hyperandrogenisation on the uterine PPAR system. Rats were treated with 2mg testosterone from Day 16 to 19 of pregnancy. Female offspring (PH group) were followed until 90 days of life, when they were killed. The PH group exhibited an anovulatory phenotype. We quantified uterine mRNA levels of PPARα (Ppara ), PPARδ (Ppard ), PPARγ (Pparg ), their regulators peroxisome proliferator-activated receptor gamma coactivator 1-alpha (Ppargc1a ) and nuclear receptor co-repressor 1 (Ncor1 ) and cyclo-oxygenase (COX)-2 (Ptgs2 ), and assessed the lipid peroxidation (LP) index and levels of glutathione (GSH) and prostaglandin (PG) E2 . The PH group showed decreased levels of all uterine PPAR isoforms compared with the control group. In addition, PGE2 and Ptgs2 levels were increased in the PH group, which led to a uterine proinflammatory environment, as was LP, which led to a pro-oxidant status that GSH was not able to compensate for. These results suggest that prenatal exposure to androgen excess has a fetal programming effect that affects the gene expression of PPAR isoforms, and creates a misbalanced oxidant-antioxidant state and a proinflammatory status.

Metformin improves ovarian insulin signaling alterations caused by fetal programming.

Insulin resistance is the decreased ability of insulin to mediate metabolic actions. In the ovary, insulin controls ovulation and oocyte quality. Alterations in ovarian insulin signaling pathway could compromise ovarian physiology. Here, we aimed to investigate the effects of fetal programming on ovarian insulin signaling and evaluate the effect of metformin treatment. Pregnant rats were hyperandrogenized with testosterone and female offspring born to those dams were employed; at adulthood, prenatally hyperandrogenized (PH) offspring presented two phenotypes: irregular ovulatory (PHiov) and anovulatory (PHanov). Half of each group was orally treated with metformin. Metformin treatment improved the estrous cyclicity in both PH groups. Both PH groups showed low mRNA levels of IR, IRS1 and Glut4. IRS2 was decreased only in PHanov. Metformin upregulated the mRNA levels of some of the mediators studied. Protein expression of IR, IRS1/2 and GLUT4 was decreased in both PH groups. In PHiov, metformin restored the expression of all the mediators, whereas, in PHanov, metformin restored only that of IR and IRS1/2. IRS1 phosphorylation was measured in tyrosine residues, which activates the pathway, and in serine residues, which impairs insulin action. PHiov presented high IRS1 phosphorylation on tyrosine and serine residues, whereas PHanov showed high serine phosphorylation and low tyrosine phosphorylation. Metformin treatment lowered serine phosphorylation only in PHanov rats. Our results suggest that PHanov rats have a defective insulin action, partially restored with metformin. PHiov rats had less severe alterations, and metformin treatment was more effective in this phenotype.

Treatment with the synthetic PPARG ligand pioglitazone ameliorates early ovarian alterations induced by dehydroepiandrosterone in prepubertal rats.

BACKGROUND: Peroxisome proliferator-activated receptor gamma (PPARG) is a nuclear factor that may act on the early development of ovarian follicles and on follicular steroidogenesis. However, the exact mechanism of PPARG action remains unknown. We have previously found that androgen excess alters early ovarian function and the PPARG system. The aim of the present study was to evaluate whether PPARG activation (using the synthetic ligand pioglitazone (PGZ)) ameliorates the alterations in early ovarian function induced by androgen excess. METHODS: Female prepubertal rats were treated with equine chorionic gonadotropin (eCG) to induce folliculogenesis, together with dehydroepiandrosterone (DHEA) to induce hyperandrogenism and/or PGZ to evaluate PPARG activation. We assessed i) very early ovarian folliculogenesis, ii) PPARG activation, iii) ovarian steroidogenic enzymes, iv) the estradiol/testosterone ratio, v) the ovarian inflammatory status and vi) oxidative stress. RESULTS: PGZ prevented the inactivation of ovarian PPARG induced by androgen excess by increasing PPARG itself and the gene expression of PPARG-coactivator 1 alpha (PGC1A), and by decreasing the gene expression of nuclear co-repressor (NCOR). PGZ also prevented the altered ovarian steroidogenesis, pro-inflammatory status and oxidative stress induced by androgen excess. CONCLUSIONS: Our findings suggest that PPARG activation plays important roles in modulating early ovarian function, and highlight the importance of understanding the role(s) of PPARG activation in the ovary, and the possible involvement in the treatment of ovarian pathologies, and/or the impact in regulating/improving fertility.

Uterine Function: From Normal to Polycystic Ovarian Syndrome Alterations.

BACKGROUND: The endometrium is one of the most important female reproductive organs. Polycystic ovarian syndrome (PCOS) is a reproductive and endocrine pathology that affect women of reproductive age. PCOS negatively affects the endometrium, leading to implantation failure and proliferative aberrations. METHODS: We conducted a search at the http://www.ncbi.nlm.nhi.gov/pubmed/electronic database using the following key words: endometrial steroid receptors, endometrium, uterine function, endometrium and PCOS, implantation window, implantation and PCOS, implantation markers, inflammation, oxidative stress. We selected the articles based on their titles and abstracts, then we analyzed the full text and classified the articles depending on the information provided according to the sections of the present review. RESULTS: The endocrine and metabolic abnormalities displayed in women with PCOS promote complex effects on the endometrium, leading to a low rate of implantation and even infertility. Women with PCOS show alterations in the Hypothalamic-Pituitary- Ovarian axis, which results in constant circulating levels of estrogen, similar to those at the early follicular phase, and a deficiency in the withdrawal of estrogen and progesterone. Besides this deficiency in the withdrawal of estrogen and progesterone, the insulin/ glucose pathway, adhesion molecules, cytokines and the inflammatory cascade, together with the establishment of a pro-oxidative status, lead to an imbalance in the uterine function, which in turn leads to implantation failure or even endometrial cancer. CONCLUSION: Women with PCOS display a dysregulation of the Hypothalamic-Pituitary- Ovarian axis, which alters the steroid pathway. In addition, the deficiency in the withdrawal of estrogen and progesterone in the endometrium results in abnormal endometrial cellular proliferation. The imbalance in adipose tissue observed in PCOS patients reinforces the increase in circulating hormones. The present review describes the role of hormones, metabolites, cytokines, adhesion molecules and the insulin/glucose pathway related to the uterine endometrium in women with PCOS and their role in implantation failure and development of endometrial cancer.

Lipid Accumulation Product (LAP) and Visceral Adiposity Index (VAI) as Markers of Insulin Resistance and Metabolic Associated Disturbances in Young Argentine Women with Polycystic Ovary Syndrome.

Polycystic ovary syndrome (PCOS) is an endocrine disorder. PCOS women are at high risk of developing insulin resistance (IR) and cardiovascular disorders since young age. We aimed to study the reliability of lipid accumulation product (LAP) and visceral adiposity index (VAI) as markers of metabolic disturbances (MD) associated with IR in young reproductive aged PCOS patients. We also evaluated the association between LAP and VAI and the presence of hyperandrogenism. In a cross-sectional study, 110 PCOS patients and 88 control women (18-35 years old) were recruited. PCOS patients were divided into 2 groups, as hyperandrogenic and non-hyperandrogenic considering the signs of hyperandrogenism (clinical or biochemical). Anthropometric measurements were taken and blood samples collected. Metabolic and anthropometric characteristics and their association with IR and associated MD were evaluated and LAP and VAI were calculated. LAP and VAI were compared with TC/HDL-c and TG/HDL-c to define the best markers of MD in this population. Independently of the phenotype, young PCOS patients showed high IR and dyslipidemia. Both LAP and VAI showed to be more effective markers to assess MD and IR in these young women than TG/HDL-c or TC/HDL-c [cut-off values: LAP: 18.24 (sensitivity: 81.43% specificity: 73.49%), positive predictive value (PPV): 75.0%, negative predictive value (NPV): 77.27%, VAI: 2.19 (sensitivity: 81.16% specificity: 72.15% PPV: 74.65% NPV: 72.22%)]. LAP and VAI are representative markers to assess MD associated with IR in young PCOS patients. All PCOS patients, independently of their androgenic condition, showed high metabolic risk.

Effect of hyperandrogenism on ovarian function.

The objective of this work was to study the ovarian function when follicular development is induced during a hyperandrogenic condition. Female rats were injected with either equine chorionic gonadotropin (eCG group) to induce folliculogenesis or eCG together with DHEA to induce folliculogenesis in a hyperandrogenic condition (eCG+HA group). The control group was injected with vehicle. Ovarian mRNA levels of the peroxisome proliferator-activated receptor gamma (PPARγ) co-activator PGC1α, the PPARγ co-repressor NCoR, the main enzymes involved in the ovarian steroidogenesis (CYP17, 3ß-hydroxysteroid dehydrogenase (3ß-HSD), 17ß-HSD, and CYP19A), and cyclooxygenase 2 (COX2) were evaluated only by real-time PCR. COX2 was evaluated by both real-time PCR and western blot. Serum steroid hormones and both the oxidative and inflammatory statuses were also quantified. We found that eCG-induced folliculogenesis induced increased mRNA levels of PGC1α and decreased those of NCoR when compared with controls. In addition, we found an increase in serum estradiol (E2) levels and enhanced mRNA expression of CYP19A. A pro-inflammatory status and a pro-oxidant status were also established. When folliculogenesis was induced in a hyperandrogenic condition, the mRNA levels of the PPARγ co-repressor NCoR remained higher than in controls and the pro-inflammatory and pro-oxidant statuses were enhanced. In addition, the enzymes involved in ovarian steroidogenesis were altered leading to the accumulation of testosterone and an unfavorable E2/testosterone ratio. These alterations led to abnormal follicular development.

Prenatal hyperandrogenism and lipid profile during different age stages: an experimental study.

OBJECTIVE: The present study investigates the effect of prenatal hyperandrogenization on lipid metabolism and oxidant/antioxidant balance. DESIGN: Experimental study. SETTING: Research institute. ANIMAL(S): Pregnant Sprague Dawley rats were subcutaneously injected with 2 mg free T between days 16 and 19 of pregnancy, and controls (C) received vehicle (0.1 mL of sesame oil). Prenatally hyperandrogenized female offspring (T2) had a condition that resembles polycystic ovary (PCO). Animals were weighed and killed at 21 and 60 days of age (N = 15 rats/group). INTERVENTION(S): Ovarian tissue and truncal blood were obtained from the C and T2 groups. MAIN OUTCOME MEASURE(S): Circulating lipid profile (total cholesterol, high-density lipoprotein [HDL], low-density lipoprotein [LDL] cholesterol, and triglycerides) was quantified by colorimetric-enzymatic methods. Ovarian oxidative stress was evaluated by quantifying lipid peroxidation and glutathione content by spectofotometric assays. Ovarian fat content was evaluated by Red Oil staining and ovarian messenger RNA (mRNA) expression of peroxisome proliferator-activated receptor gamma (PPAR-γ) by real-time polymerase chain reaction (PCR). RESULT(S): At 60 days of age, 100% of group C rats and 20% of group T2 rats ovulated. At 21 days of age the T2 rats displayed lower body weight than C rats; however, at 60 days of age T2 and C rats showed similar body weights. The lipid profile (total cholesterol, LDL cholesterol, HDL cholesterol, and triglycerides) was altered in the anovulatory and ovulatory phenotype of the T2 group, but the levels were higher in the anovulatory phenotype. Lipid peroxidation of rats at 21 and 60 days of age from T2 was similar to C but the antioxidant glutathione level was decreased in 21-day-old rats compared with C rats. The lipid content of ovarian tissue, determined by Red Oil staining, was higher in the T2 than in the C group. The mRNA expression of ovarian PPAR-γ, quantified by real time PCR, decreased in anovulatory rats at 60 days of age from T2 compared to C rats. CONCLUSION(S): Our findings reveal the importance of evaluating the complete lipid profile, especially at early stages of life after the prenatal hyperandrogenism condition. In addition, we demonstrated that the antioxidant-reduced glutathione would represent a good marker of oxidative stress as it is altered before lipid peroxidation. Prenatal hyperandrogenization also alters the gene expression of PPAR-γ in rats. Here we demonstrated for the first time that abnormalities in PPAR-γ and lipid profile were higher in rats showing an anovulatory phenotype than those displaying an ovulatory phenotype.

[The role of prenatal hyperandrogenism on lipid metabolism during adult life in a rat model]. / Hiperandrogenización prenatal en ratas y el metabolismo lipídico en la vida adulta.

Polycystic ovary syndrome (PCOS) is one of the commonest endocrine diseases that affect women in their reproductive ages; however, the etiology of the syndrome remains unknown. A hypothesis proposes that during gestation increased exposure of androgen would induce fetal programming that may increase the risk of PCOS development during the adult life. By means of a prenatally hyperandrogenized (HA) rat model we demonstrated the importance of determining the lipid profile at early ages. HA induced two different phenotypes: ovulatory and anovulatory PCOS. HA did not modify total cholesterol but decreased HDL cholesterol and increased both LDL and tryglicerides (TG) when compared with controls. Both, the ratio total cholesterol: HDL (marker of cardiovascular risk) and TG:HDL (marker of metabolic syndrome) were increased in the HA group with respect to controls. In addition, these abnormalities were stronger in the anovulatory than ovulatory phenotype. Our results point out the need to find early markers of PCOS in girls or adolescents with increased risk to develop PCOS (as in daughters of women with PCOS).

Hiperandrogenización prenatal en ratas y el metabolismo lipídico en la vida adulta / The role of prenatal hyperandrogenism on lipid metabolism during adult life in a rat model

El síndrome del ovario poliquístico (PCOS) es una afección de alta incidencia en mujeres en edad fértil. Si bien la etiología de la enfermedad se desconoce, se cree que la exposición a andrógenos durante la vida intrauterina generaría reprogramación fetal afectando vías endocrinas y metabólicas que, junto a alteraciones génicas y ambientales, inducirían la aparición de PCOS en etapas muy tempranas de la vida. Es por ello que se buscan marcadores tempranos del desarrollo de PCOS. Utilizando un modelo murino de hiperandrogenización prenatal (HA) recreamos dos fenotipos de PCOS: ovulatorio y anovulatorio. La HA no alteró el colesterol circulante pero disminuyó el colesterol HDL y aumentó el LDL y los triglicéridos (TG) con respecto a los controles. La relación colesterol total/HDL como marcador de riesgo cardiovascular y la relación TG/HDL se vieron incrementadas con respecto a los controles, resultando mayor en el grupo PCOS anovulatorio. El presente trabajo demuestra la importancia de la determinación del perfil lipídico a edades tempranas en poblaciones de riesgo (como es el caso de hijas de madres con PCOS).

Polycystic ovary syndrome (PCOS) is one of the commonest endocrine diseases that affect women in their reproductive ages; however, the etiology of the syndrome remains unknown. A hypothesis proposes that during gestation increased exposure of androgen would induce fetal programming that may increase the risk of PCOS development during the adult life. By means of a prenatally hyperandrogenized (HA) rat model we demonstrated the importance of determining the lipid profile at early ages. HA induced two different phenotypes: ovulatory and anovulatory PCOS. HA did not modify total cholesterol but decreased HDL cholesterol and increased both LDL and tryglicerides (TG) when compared with controls. Both, the ratio total cholesterol: HDL (marker of cardiovascular risk) and TG:HDL (marker of metabolic syndrome) were increased in the HA group with respect to controls. In addition, these abnormalities were stronger in the anovulatory than ovulatory phenotype. Our results point out the need to find early markers of PCOS in girls or adolescents with increased risk to develop PCOS (as in daughters of women with PCOS).

Hiperandrogenización prenatal en ratas y el metabolismo lipídico en la vida adulta / The role of prenatal hyperandrogenism on lipid metabolism during adult life in a rat model

El síndrome del ovario poliquístico (PCOS) es una afección de alta incidencia en mujeres en edad fértil. Si bien la etiología de la enfermedad se desconoce, se cree que la exposición a andrógenos durante la vida intrauterina generaría reprogramación fetal afectando vías endocrinas y metabólicas que, junto a alteraciones génicas y ambientales, inducirían la aparición de PCOS en etapas muy tempranas de la vida. Es por ello que se buscan marcadores tempranos del desarrollo de PCOS. Utilizando un modelo murino de hiperandrogenización prenatal (HA) recreamos dos fenotipos de PCOS: ovulatorio y anovulatorio. La HA no alteró el colesterol circulante pero disminuyó el colesterol HDL y aumentó el LDL y los triglicéridos (TG) con respecto a los controles. La relación colesterol total/HDL como marcador de riesgo cardiovascular y la relación TG/HDL se vieron incrementadas con respecto a los controles, resultando mayor en el grupo PCOS anovulatorio. El presente trabajo demuestra la importancia de la determinación del perfil lipídico a edades tempranas en poblaciones de riesgo (como es el caso de hijas de madres con PCOS).(AU)

Polycystic ovary syndrome (PCOS) is one of the commonest endocrine diseases that affect women in their reproductive ages; however, the etiology of the syndrome remains unknown. A hypothesis proposes that during gestation increased exposure of androgen would induce fetal programming that may increase the risk of PCOS development during the adult life. By means of a prenatally hyperandrogenized (HA) rat model we demonstrated the importance of determining the lipid profile at early ages. HA induced two different phenotypes: ovulatory and anovulatory PCOS. HA did not modify total cholesterol but decreased HDL cholesterol and increased both LDL and tryglicerides (TG) when compared with controls. Both, the ratio total cholesterol: HDL (marker of cardiovascular risk) and TG:HDL (marker of metabolic syndrome) were increased in the HA group with respect to controls. In addition, these abnormalities were stronger in the anovulatory than ovulatory phenotype. Our results point out the need to find early markers of PCOS in girls or adolescents with increased risk to develop PCOS (as in daughters of women with PCOS).(AU)

Hyperthyroidism advances luteolysis in the pregnant rat through changes in prostaglandin balance.

OBJECTIVE: To investigate the underlying mechanisms implicated in the premature luteolysis induced by hyperthyroidism in pregnant rats. DESIGN: Experimental basic study. SETTING: Research institute. ANIMAL(S): Groups of 6-8 adult female Wistar rats were injected SC daily with T(4) (0.25 mg/kg) or vehicle, starting 8 days before mating, and killed by decapitation on days 19 (G19), 20 (G20), and 21 (G21) of pregnancy. INTERVENTION(S): Corpora lutea and truncal blood of control and hyperthyroid rats were obtained. MAIN OUTCOME MEASURE(S): Circulating and intraluteal hormones were determined by using RIA and luteal messenger RNA (mRNA) expression of enzymes and factors involved in P synthesis and metabolism by reverse transcriptase-polymerase chain reaction. 20α-Hydroxysteroid dehydrogenase (20αHSD) mRNA and protein expression was also determined by quantitative reverse transcriptase-polymerase chain reaction and Western blot. RESULT(S): Hyperthyroidism advanced luteolysis and 20αHSD expression induction by one day without changes in enzymes involved in P synthesis, decreased circulating E(2) and luteal estrogen receptor beta, and increased luteal prostaglandin F(2α) on G19 and G20 and prostaglandin E(2) on G19, while decreasing it on G20. Thus, decreased estrogenic influence and high prostaglandin F(2α)/prostaglandin E(2) ratio favors premature induction of 20αHSD on hyperthyroid rats. CONCLUSION: Hyperthyroidism affects luteolysis in pregnant rats through alterations in luteal prostaglandin balance and decreased luteotrophic factors favoring the luteolytic action of prostaglandin F(2α) that induces premature 20αHSD expression that in turn advances circulating P fall and delivery.

Hyperandrogenism alters intraovarian parameters during early folliculogenesis in mice.

This study aimed to investigate how hyperandrogenism affects early folliculogenesis. Hyperandrogenism was induced in prepuberal female BALB/c mice by daily s.c. injection of dehydroepiandrosterone (60 mg/kg body weight in 0.1 ml sesame oil) for 10 consecutive days. Although hyperandrogenism increased the growth rate of primary follicles, it also increased ovarian oxidative stress (evaluated by the increase in lipid peroxidation, the decrease in superoxide dismutase activity and the fact that glutathione content was not modified). By using the annexin V/cytometry assay it was found that the excess of androgens decreased viable ovarian cells and increased early apoptotic ones. The increased lipid peroxidation induced enhanced ovarian prostaglandin E production. In addition, hyperandrogenism increased the number of T lymphocytes that infiltrate ovarian tissue and modified their phenotype (decreased CD4+ or helper and increased the suppressor/cytotoxic CD8+). The excess of androgens decreased the ovarian expression of the long isoform of leptin receptor (Ob-Rb, the only isoform expressed in the ovarian tissue) when compared with controls. All these alterations increased serum concentrations of oestradiol, a pro-apoptotic agent. It is concluded that the excess of androgens impairs early follicular development by modulating some endocrine and immune parameters that are either directly or indirectly related to follicular atresia.

Effect of DHEA and metformin on corpus luteum in mice.

We evaluated the effect of hyperandrogenism in ovaries with functional and regressing corpora lutea (CL) and the action of metformin in preventing these possible alterations using a mouse model. To obtain a CL functional for 9+/-1 days, immature female mice of the BALB/c strain were injected i.p. with 10 IU/mouse of pregnant mare's serum gonadotropin (PMSG). DHEA (60 mg/kg body weight s.c., 24 and 48 h prior to kill) decreased both serum progesterone (P) and estradiol (E(2)) levels and increased the activity of superoxide dismutase (SOD) from ovaries with functional CL (on day 5 after PMSG). It increased P and E(2) and the activities of SOD and catalase (CAT) and decreased lipoperoxidation of ovaries with regressing CL (on day 9 after PMSG). Treatment with DHEA did not affect the production of prostaglandin F(2alpha) (PGF(2alpha)) or PGE by ovaries with functional CL, whereas DHEA decreased PGF(2alpha) and increased PGE production by ovaries with regressing CL. Metformin (50 mg/kg body weight, orally) given together with DHEA restored E(2) levels from mice with ovaries with functional CL and serum P, PGF(2alpha) and PGE levels, and oxidative balance in mice with ovaries with regressing CL. Metformin alone was able to modulate serum P and E(2) levels, lipoperoxidation, SOD and CAT, and the 5,5-dimethyl-1-pyrroline N-oxide/(*)OH signal. These findings suggest that hyperandrogenism is able to induce or to rescue CL from luteolysis and metformin treatment is able to prevent these effects.

Regulation of functional and regressing stages of corpus luteum development in mice. Role of reactive oxygen species.

The endocrine and immune systems modulate ovarian function. The aim of the present work was to compare the status of various modulating factors in two well-defined stages of corpus luteum (CL) development (the functional stage and the regressing stage) by means of a gonadotropin-synchronised mouse model. At the regressing stage of CL development, we found that ovarian tissue showed increased prostaglandin (PG) F(2alpha) and diminished PGE levels concomitantly with enhanced protein abundance of ovarian cyclooxygenase 2, the inducible isoform of the limiting enzyme of PG synthesis. We also found both enhanced lipid peroxidation and enhanced total superoxide dismutase activity, as well as inhibited catalase activity and inhibited total hydroxyl radical scavenger capacity, when compared with ovaries at the functional stage. In addition, at the regressing stage we observed an increased percentage of CD8+ (cytotoxic/suppressor) T-cells and a decreased percentage of CD4+ (helper) T-cells from ovarian-draining lymph nodes. Also, the serum interleukin (IL)-2, IL-4 and IL-10 were diminished as compared with the functional stage. We conclude that a pro-oxidant status together with a pro-inflammatory response is responsible for the loss of luteal function.

Hypothyroidism prolongs corpus luteum function in the pregnant rat.

It has been shown that hypothyroidism in the rat produces a prolongation of pregnancy associated with a delay in the fall of circulating progesterone (P4) at term. The aim of the present work is to determine whether the delayed P4 decline in hypothyroid mother rats is due to a retarded induction of P4 degradation to 20alphaOH P4 or to a stimulation of its synthesis, and to investigate the possible mechanisms that may underlie the altered luteal function. We determined by RIA the circulating profile of the hormones (TSH, PRL, LH, P4, PGF2alpha, and PGE2) involved in luteal regulation at the end of pregnancy and, by semiquantitative RT-PCR, the expression of factors involved in P4 synthesis (CytP450scc, StAR, 3betaHSD, PRLR) and metabolism (20alphaHSD, PGF2alphaR, iNOS and COX2). Our results show that the delay in P4 decline and parturition is the resultant of retarded luteal regression, caused by a combination of decreases in luteolytic factors, mainly luteal PGF2alpha, iNOS mRNA expression and also circulating LH, and increased synthesis or action of luteotrophic factors, such as luteal and circulating PGE2 and circulating PRL. All these changes may be direct causes of the decreased 20alphaHSD mRNA and protein (measured by western blot analysis) expression, which in the presence of unchanged expression of the factors involved in P4 synthesis results in elevated luteal and circulating P4 that prolonged pregnancy and also may favor longer survival of the corpus luteum.

The influence of dehydroepiandrosterone on early pregnancy in mice.

The aim of the present report was to study the role of high levels of dehydroepiandrosterone (DHEA) on the ovarian function and embryonic resorption during early pregnancy in BALB/c mice. Pregnant animals were injected with DHEA following both the post-implantatory (DHEA-2) and peri-implantatory (DHEA-6) models. Morphological studies of implantation sites showed 40% of embryonic resorption in the DHEA-2 group while 100% of resorption was observed in the DHEA-6 group. Serum samples of both DHEA-2 and DHEA-6 groups showed higher estradiol levels and a lower progesterone concentration than those of control groups. Ovarian prostaglandin E levels after both DHEA-2 and DHEA-6 treatments increased when compared to control groups. The antioxidant metabolite glutathione diminished during both DHEA treatments. In summary, the data presented here suggest that DHEA treatment during early pregnancy modulates the ovarian function and is responsible for embryonic resorption with different degrees depending on when it is administered.

Effects of dehydroepiandrosterone on ovarian cystogenesis and immune function.

The purpose of the present report was to study the possible relationship between ovarian functionality and the immune response during cystogenesis induced by androgenization with dehydroepiandrosterone (DHEA). Daily injection of DHEA (6 mg/kg body weight) for 20 consecutive days induced ovarian cysts in BALB/c mice. As markers of ovarian function, serum estradiol (E) and progesterone (P) and the ovarian inmunomodulator prostaglandin E (PGE) were analyzed. In order to know how the integrity of the tissue was altered after induction of cystogenesis, the oxidative status was also evaluated. Serum E and P levels, and ovarian PGE concentration, were increased in animals with cysts compared with healthy controls. The oxidant status (quantified by malondialdehyde (MDA) formed after the breakdown of the cellular membrane by free radical mechanisms) was augmented, meanwhile the antioxidant (evaluated by the glutathione (GSH) content) diminished during the induction of cystogenesis. Both immunohistochemical and flow cytometry assays demonstrated that DHEA treatment increased the number of T lymphocytes infiltrating ovarian tissue. Therefore, while ovarian controls showed equivalent expression of CD4+ and CD8+ T cell subsets, injection of DHEA yielded a selective ovarian T cell infiltration as demonstrated by enhanced CD8+ and diminished CD4+ T lymphocyte expression. These results show that the development of cysts involves changes in ovarian function and an imbalance in the oxidant-antioxidant equilibrium. We observed also both an increased and selective T lymphocyte infiltration.