Effects of testosterone on fat cell lipolysis. Species differences and possible role in polycystic ovarian syndrome

Polycystic ovary syndrome

Despite affecting ~11-13% of women globally, polycystic ovary syndrome (PCOS) is a substantially understudied condition. PCOS, possibly extending to men's health, imposes a considerable health and economic burden worldwide. Diagnosis in adults follows the International Evidence-based Guideline for the Assessment and Management of Polycystic Ovary Syndrome, requiring two out of three criteria - clinical or biochemical hyperandrogenism, ovulatory dysfunction, and/or specific ovarian morphological characteristics or elevated anti-Müllerian hormone. However, diagnosing adolescents omits ovarian morphology and anti-Müllerian hormone considerations. PCOS, marked by insulin resistance and hyperandrogenism, strongly contributes to early-onset type 2 diabetes, with increased odds for cardiovascular diseases. Reproduction-related implications include irregular menstrual cycles, anovulatory infertility, heightened risks of pregnancy complications and endometrial cancer. Beyond physiological manifestations, PCOS is associated with anxiety, depression, eating disorders, psychosexual dysfunction and negative body image, collectively contributing to diminished health-related quality of life in patients. Despite its high prevalence persisting into menopause, diagnosing PCOS often involves extended timelines and multiple health-care visits. Treatment remains ad hoc owing to limited understanding of underlying mechanisms, highlighting the need for research delineating the aetiology and pathophysiology of the syndrome. Identifying factors contributing to PCOS will pave the way for personalized medicine approaches. Additionally, exploring novel biomarkers, refining diagnostic criteria and advancing treatment modalities will be crucial in enhancing the precision and efficacy of interventions that will positively impact the lives of patients.

White-brown adipose tissue interplay in polycystic ovary syndrome: Therapeutic avenues

This study highlights the therapeutic potential of activating brown adipose tissue (BAT) for managing polycystic ovary syndrome (PCOS), a prevalent endocrine disorder associated with metabolic and reproductive abnormalities. BAT plays a crucial role in regulating energy expenditure and systemic insulin sensitivity, making it an attractive target for the treatment of obesity and metabolic diseases. Recent research suggests that impaired BAT function and mass may contribute to the link between metabolic disturbances and reproductive issues in PCOS. Additionally, abnormal white adipose tissue (WAT) can exacerbate these conditions by releasing adipokines and nonesterified fatty acids. In this review, we explored the impact of WAT changes on BAT function in PCOS and discussed the potential of BAT activation as a therapeutic strategy to improve PCOS symptoms. We propose that BAT activation holds promise for managing PCOS; however, further research is needed to confirm its efficacy and to develop clinically feasible methods for BAT activation.

Protein Expression and Bioinformatics Study of Granulosa Cells of Polycystic Ovary Syndrome Expressed Under the Influence of DHEA

Background

The reproductive system is heavily dependent on ovarian follicles, which are made up of germ cells (oocytes) and granulosa cells (GCs), including cumulus granulosa cells (CGCs) and mural granulosa cells (MGCs). Understanding their normal and steroid-induced functions is the key to understanding the pathophysiology of endocrinal diseases in women.

Objective

This study investigated the differentially expressed proteins by CGCs and MGCs of patients with polycystic ovarian syndrome (PCOS) and without subsequent exposure to dehydroepiandrosterone sulfate (DHEAS) and functional differentiation.

Design

The present study was observational and experimental study carried out in hospital involving 80 female patients undergoing IVF for infertility.

Methods

In this study, we isolated CGCs and MGCs from the follicular fluid of both PCOS and non-PCOS patients undergoing in vitro fertilization (IVF). The cells were cultured and treated with DHEAS for 48 hours, and these cells were extracted, digested, and analyzed by tandem mass spectrometry followed by processing of the results using open-source bioinformatics tools.

Results

The present investigation discovered 276 and 341 proteins in CGCs and MGCs, respectively. DHEAS reduced the number of proteins expressed by CGCs and MGCs to 34 and 57 from 91 and 94, respectively. Venn results of CGCs revealed 49, 53, 36, and 21 proteins in normal CGCs, PCOS-CGCs, post-DHEAS, and PCOS-CGCs, respectively. Venn analysis of MGCs showed 51 proteins specific to PCOS and 29 shared by normal and PCOS samples after DHEAS therapy. MGCs express the most binding and catalytic proteins, whereas CGCs express transporter-related proteins. A protein pathway study demonstrated considerable differences between normal and PCOS samples, while DHEAS-treated samples of both cell lines showed distinct pathways. String findings identified important network route components such as albumin, actin, apolipoprotein, complement component C3, and heat shock protein.

Conclusion

This is the first study to show how DHEAS-induced stress affects the expression of proteins by MGCs and CGCs isolated from normal and PCOS patients. Further studies are recommended to identify PCOS biomarkers from CGCs and MGCs expressed under the influence of DHEAS.

An Evolutionary Model for the Ancient Origins of Polycystic Ovary Syndrome

Polycystic ovary syndrome (PCOS) is a common endocrinopathy of reproductive-aged women, characterized by hyperandrogenism, oligo-anovulation and insulin resistance and closely linked with preferential abdominal fat accumulation. As an ancestral primate trait, PCOS was likely further selected in humans when scarcity of food in hunter-gatherers of the late Pleistocene additionally programmed for enhanced fat storage to meet the metabolic demands of reproduction in later life. As an evolutionary model for PCOS, healthy normal-weight women with hyperandrogenic PCOS have subcutaneous (SC) abdominal adipose stem cells that favor fat storage through exaggerated lipid accumulation during development to adipocytes in vitro. In turn, fat storage is counterbalanced by reduced insulin sensitivity and preferential accumulation of highly lipolytic intra-abdominal fat in vivo. This metabolic adaptation in PCOS balances energy storage with glucose availability and fatty acid oxidation for optimal energy use during reproduction; its accompanying oligo-anovulation allowed PCOS women from antiquity sufficient time and strength for childrearing of fewer offspring with a greater likelihood of childhood survival. Heritable PCOS characteristics are affected by today's contemporary environment through epigenetic events that predispose women to lipotoxicity, with excess weight gain and pregnancy complications, calling for an emphasis on preventive healthcare to optimize the long-term, endocrine-metabolic health of PCOS women in today's obesogenic environment.

Interplay of Cortisol, Testosterone, and Abdominal Fat Mass in Normal-weight Women With Polycystic Ovary Syndrome

Context

Ovarian and adrenal steroidogenesis underlie endocrine-metabolic dysfunction in polycystic ovary syndrome (PCOS). Adipocytes express aldo-keto reductase 1C3 and type 1 11β-hydroxysteroid dehydrogenase, which modulate peripheral androgen and cortisol production.

Objectives

To compare serum adrenal steroids, including 11-oxygenated androgens (11-oxyandrogens), cortisol, and cortisone between normal-weight women with PCOS and body mass index- and age-matched ovulatory women with normal-androgenic profiles (controls), and assess whether adrenal steroids associate with abdominal adipose deposition.

Design

Prospective, cross-sectional, cohort study.

Setting

Academic medical center.

Patients

Twenty normal-weight women with PCOS and 20 body mass index-/age-matched controls.

Interventions

Blood sampling, IV glucose tolerance testing, and total-body dual-energy x-ray absorptiometry.

Main Outcome Measures

Clinical characteristics, hormonal concentrations, and body fat distribution.

Results

Women with PCOS had higher serum total/free testosterone (T) and androstenedione (A4) levels and a greater android/gynoid fat mass than controls (androgens P < .001; android/gynoid fat mass ratio, P = .026). Serum total/free T and A4 levels correlated positively with android/gynoid fat mass ratio in all women combined (P < .025, all values). Serum 11ß-hydroxyA4, 11-ketoA4, 11ß-hydroxyT, 11-ketoT, cortisol, and cortisone levels were comparable between female types and unrelated to body fat distribution. Serum 11-oxyandrogens correlated negatively with % total body fat, but lost significance adjusting for cortisol. Serum cortisol levels, however, correlated inversely with android fat mass (P = .021), with a trend toward reduced serum cortisol to cortisone ratio in women with PCOS vs controls (P = .075), suggesting diminished 11β-hydroxysteroid dehydrogenase activity.

Conclusion

Reduced cortisol may protect against preferential abdominal fat mass in normal-weight PCOS women with normal serum 11-oxyandrogens.

Serum amyloid A and metabolic disease: evidence for a critical role in chronic inflammatory conditions

Serum amyloid A (SAA) subtypes 1-3 are well-described acute phase reactants that are elevated in acute inflammatory conditions such as infection, tissue injury, and trauma, while SAA4 is constitutively expressed. SAA subtypes also have been implicated as playing roles in chronic metabolic diseases including obesity, diabetes, and cardiovascular disease, and possibly in autoimmune diseases such as systemic lupus erythematosis, rheumatoid arthritis, and inflammatory bowel disease. Distinctions between the expression kinetics of SAA in acute inflammatory responses and chronic disease states suggest the potential for differentiating SAA functions. Although circulating SAA levels can rise up to 1,000-fold during an acute inflammatory event, elevations are more modest (∼5-fold) in chronic metabolic conditions. The majority of acute-phase SAA derives from the liver, while in chronic inflammatory conditions SAA also derives from adipose tissue, the intestine, and elsewhere. In this review, roles for SAA subtypes in chronic metabolic disease states are contrasted to current knowledge about acute phase SAA. Investigations show distinct differences between SAA expression and function in human and animal models of metabolic disease, as well as sexual dimorphism of SAA subtype responses.

Polycystic ovary syndrome and adipose tissue

Polycystic ovary syndrome (PCOS) is the most common endocrine metabolic disorder in women of reproductive age. Typically, it is associated with ovulatory dysfunction: dysovulation or anovulation, and symptoms of hyperandrogenism. It incurs risk of metabolic disorders such as diabetes, dyslipidemia and fatty liver. As a key endocrine organ in metabolic homeostasis, adipose tissue is often implicated in these complications. Studies of white adipose tissue (WAT) in PCOS have focused on the mechanism of insulin resistance in this tissue. Clinically, abnormalities in WAT distribution are seen, with decreased waist-to-hip ratio and increased ratio of adipose to lean mass. Such abnormalities are greater when total circulating androgens are elevated. At tissue level, white adipocyte hyperplasia occurs, along with infiltration of macrophages. Secretion of adipokines, cytokines and chemo-attractant proteins is increased in a pro-inflammatory manner, leading to reduced insulin sensitivity via alteration of glucose transporters, and hence decreased glucose uptake. The kinetics of non-esterified fatty acids (or free fatty acids) is also altered, leading to lipotoxicity. In recent years, brown adipose tissue (BAT) has been studied in women with PCOS. Although abundance is low in the body, BAT appears to play a significant role in energy expenditure and metabolic parameters. Both supra-clavicular skin temperature, which reflects BAT activity, and BAT mass are reduced in women with PCOS. Moreover, BAT mass and body mass index (BMI) are inversely correlated in patients. In the adipocyte, increased total circulating androgen levels reduce expression of uncoupling protein 1 (UCP1), a key protein in the brown adipocyte, leading to reduced biogenesis and mitochondrial respiration and hence a reduction in post-prandial thermogenesis. BAT is currently being investigated as a possible new therapeutic application.

Randomized clinical trial: effect of low-dose flutamide on abdominal adipogenic function in normal-weight women with polycystic ovary syndrome

OBJECTIVE

To examine whether low-dose flutamide administration to normal-weight women with polycystic ovary syndrome (PCOS) reduces abdominal fat deposition, attenuates accelerated lipid accumulation in newly formed adipocytes derived from subcutaneous (SC) abdominal adipose stem cells (ASCs), and/or alters glucose-lipid metabolism.

DESIGN

A double-blind, placebo-controlled randomized clinical trial.

SETTING

An academic medical center.

PATIENT(S)

Twelve normal-weight women with PCOS and 12 age- and body mass index-matched controls.

INTERVENTION(S)

Women underwent circulating hormonal and metabolic determinations, intravenous glucose tolerance testing, total body dual-energy roentgenogram absorptiometry, and SC abdominal fat biopsy. Interventions were repeated in women with PCOS after 6-month administration of flutamide (125 mg orally daily) vs. placebo.

MAIN OUTCOME MEASURE(S)

Clinical parameters and lipid accumulation in newly formed adipocytes derived from SC abdominal ASCs in vitro were compared between controls and the women with PCOS receiving flutamide vs. placebo.

RESULTS

Serum luteinizing hormone and androgen levels as well as lipid accumulation in newly formed SC abdominal adipocytes were greater in the women with PCOS than controls. Flutamide vs. placebo reduced percent android fat, lowered serum log low-density lipoprotein and log non-high-density lipoprotein levels, and increased fasting circulating glucose levels. In all women with PCOS, changes in percent android fat positively correlated with serum log non-high-density lipoprotein and log low-density lipoprotein levels, with correlations influenced by serum free testosterone levels. Flutamide vs. placebo also attenuated lipid accumulation in newly-formed PCOS SC abdominal adipocytes in vitro relative to controls, which was unrelated to serum lipid levels.

CONCLUSION

Low-dose flutamide administration to normal-weight PCOS women reduces preferential abdominal fat deposition, attenuates accelerated lipid accumulation in newly-formed adipocytes derived from SC abdominal ASCs in vitro, and alters glucose-lipid homeostasis.

CLINICAL TRIAL REGISTRATION NUMBER

NCT01889199 (URL, clinicaltrials.gov; date of registration, 6/28/2013; enrollment date of first subject, 6/28/2013).

Integrated Analysis of the ceRNA Network and M-7474 Function in Testosterone-Mediated Fat Deposition in Pigs

Castration can significantly enhance fat deposition in pigs, and the molecular mechanism of fat deposition caused by castration and its influence on fat deposition in different parts of pigs remain unclear. RNA-seq was performed on adipose tissue from different parts of castrated and intact Yorkshire pigs. Different ceRNA networks were constructed for different fat parts. GO and KEGG pathway annotations suggested that testosterone elevates cell migration and affects differentiation and apoptosis in back fat, while it predisposes animals to glycolipid metabolism disorders and increases the expression of inflammatory cytokines in abdominal fat. The interaction between M-7474, novel_miR_243 and SGK1 was verified by dual fluorescence experiments. This ceRNA relationship has also been demonstrated in porcine preadipocytes. Overexpression of M-7474 significantly inhibited the differentiation of preadipocytes compared to the control group. When 100 nM testosterone was added during preadipocyte differentiation, the expression of M-7474 was increased, and preadipocyte differentiation was significantly inhibited. Testosterone can affect preadipocyte differentiation by upregulating the expression of M-7474, sponging novel-miR-243, and regulating the expression of genes such as SGK1. At the same time, HSD11B1 and SLC2A4 may also be regulated by the corresponding lncRNA and miRNA, which ultimately affects glucose uptake by adipocytes and leads to obesity.

Polycystic ovary syndrome as a plausible evolutionary outcome of metabolic adaptation

As a common endocrinopathy of reproductive-aged women, polycystic ovary syndrome (PCOS) is characterized by hyperandrogenism, oligo-anovulation and polycystic ovarian morphology. It is linked with insulin resistance through preferential abdominal fat accumulation that is worsened by obesity. Over the past two millennia, menstrual irregularity, male-type habitus and sub-infertility have been described in women and confirm that these clinical features of PCOS were common in antiquity. Recent findings in normal-weight hyperandrogenic PCOS women show that exaggerated lipid accumulation by subcutaneous (SC) abdominal stem cells during development to adipocytes in vitro occurs in combination with reduced insulin sensitivity and preferential accumulation of highly-lipolytic intra-abdominal fat in vivo. This PCOS phenotype may be an evolutionary metabolic adaptation to balance energy storage with glucose availability and fatty acid oxidation for optimal energy use during reproduction. This review integrates fundamental endocrine-metabolic changes in healthy, normal-weight PCOS women with similar PCOS-like traits present in animal models in which tissue differentiation is completed during fetal life as in humans to support the evolutionary concept that PCOS has common ancestral and developmental origins.

Follicular fluid lipidomic profiling reveals potential biomarkers of polycystic ovary syndrome: A pilot study

BACKGROUND

Polycystic ovary syndrome (PCOS) is a heterogeneous endocrine disorder associated with multiple metabolic conditions including obesity, insulin resistance, and dyslipidemia. PCOS is the most common cause of anovulatory infertility; however, the molecular diversity of the ovarian follicle microenvironment is not fully understood. This study aimed to investigate the follicular fluid (FF) lipidomic profiles in different phenotypes of PCOS and to explore novel lipid biomarkers.

METHODS

A total of 25 women with PCOS and 12 women without PCOS who underwent in vitro fertilization and embryo transfer were recruited, and their FF samples were collected for the lipidomic study. Liquid chromatography-tandem mass spectrometry was used to compare the differential abundance of FF lipids between patients with different PCOS phenotypes and controls. Subsequently, correlations between specific lipid concentrations in FF and high-quality embryo rate (HQER) were analyzed to further evaluate the potential interferences of lipid levels with oocyte quality in PCOS. Candidate biomarkers were then compared via receiver operating characteristic (ROC) curve analysis.

RESULTS

In total, 19 lipids were identified in ovarian FF. Of these, the concentrations of ceramide (Cer) and free fatty acids (FFA) in FF were significantly increased, whereas those of lysophosphatidylglycerol (LPG) were reduced in women with PCOS compared to controls, especially in obese and insulin-resistant groups. In addition, six subclasses of ceramide, FFA, and LPG were correlated with oocyte quality. Twenty-three lipid subclasses were identified as potential biomarkers of PCOS, and ROC analysis indicated the prognostic value of Cer,36:1;2, FFA C14:1, and LPG,18:0 on HQER in patients with PCOS.

CONCLUSIONS

Our study showed the unique lipidomic profiles in FF from women with PCOS. Moreover, it provided metabolic signatures as well as candidate biomarkers that help to better understand the pathogenesis of PCOS.

Serum Testosterone to Androstenedione Ratio Predicts Metabolic Health in Normal-Weight Polycystic Ovary Syndrome Women

Context

Increased aldo-keto reductase 1C3 (AKR1C3)-mediated conversion of androstenedione (A4) to testosterone (T) promotes lipid storage in subcutaneous (SC) abdominal adipose in overweight/obese polycystic ovary syndrome (PCOS) women.

Objective

This work examines whether an elevated serum T/A4 ratio, as a marker of enhanced AKR1C3 activity in SC abdominal adipose, predicts metabolic function in normal-weight PCOS women.

Methods

This prospective cohort study took place in an academic center and comprised 19 normal-weight PCOS women and 21 age- and body mass index–matched controls. Interventions included circulating hormone/metabolic determinations, intravenous glucose tolerance testing, total body dual-energy x-ray absorptiometry, and SC abdominal fat biopsy. Serum T/A4 ratios, hormone/metabolic measures, and AKR1C3 expression of adipocytes matured in vitro were compared between female types; serum T/A4 ratios were correlated with serum lipids, adipose insulin resistance (adipose-IR), homeostatic model assessment of insulin resistance (HOMA-IR) and insulin sensitivity (Si).

Results

Increased serum T/A4 ratios (P = .040) and log adipose-IR values (P = .002) in PCOS women vs controls were accompanied by AKR1C3 messenger RNA overexpression of PCOS adipocytes matured in vitro (P = .016). Serum T/A4 ratios in PCOS women, but not controls, negatively correlated with log triglycerides (TGs: R = –0.65, P = .002) and the TG index (R = –0.57, P = .011). Adjusting for serum free T, serum T/A4 ratios in PCOS women remained negatively correlated with log TG (R = –0.57, P = .013) and TG index (R = –0.50, P = .036), respectively, without significant relationships with other metabolic measures.

Conclusion

An elevated serum T/A4 ratio, as a marker of enhanced AKR1C3 activity in SC abdominal adipose, predicts healthy metabolic function in normal-weight PCOS women.

Exercise Training Promotes Sex-Specific Adaptations in Mouse Inguinal White Adipose Tissue

Recent studies demonstrate that adaptations to white adipose tissue (WAT) are important components of the beneficial effects of exercise training on metabolic health. Exercise training favorably alters the phenotype of subcutaneous inguinal WAT (iWAT) in male mice, including decreasing fat mass, improving mitochondrial function, inducing beiging, and stimulating the secretion of adipokines. In this study, we find that despite performing more voluntary wheel running compared with males, these adaptations do not occur in the iWAT of female mice. Consistent with sex-specific adaptations, we report that mRNA expression of androgen receptor coactivators is upregulated in iWAT from trained male mice and that testosterone treatment of primary adipocytes derived from the iWAT of male, but not female mice, phenocopies exercise-induced metabolic adaptations. Sex specificity also occurs in the secretome profile, as we identify cysteine-rich secretory protein 1 (Crisp1) as a novel adipokine that is only secreted from male iWAT in response to exercise. Crisp1 expression is upregulated by testosterone and functions to increase glucose and fatty acid uptake. Our finding that adaptations to iWAT with exercise training are dramatically greater in male mice has potential clinical implications for understanding the different metabolic response to exercise training in males and females and demonstrates the importance of investigating both sexes in studies of adipose tissue biology.

Adipocyte and steroidogenic cell cross-talk in polycystic ovary syndrome

BACKGROUND

Metabolic and endocrine alterations in women with polycystic ovary syndrome (PCOS) affect adipose tissue mass and distribution. PCOS is characterised by hyperandrogenism, obesity and adipocyte dysfunction. Hyperandrogenism in PCOS drives dysfunctional adipocyte secretion of potentially harmful adipocytokines. Glucocorticoids and sex-steroids modulate adipocyte development and function. For their part, adipocyte products interact with adrenal and ovarian steroidogenic cells. Currently, the relationship between adipocyte and steroidogenic cells is not clear, and for these reasons, it is important to elucidate the interrelationship between these cells in women with and without PCOS.

OBJECTIVE AND RATIONALE

This comprehensive review aims to assess current knowledge regarding the interrelationship between adipocytes and adrenal and ovarian steroidogenic cells in animal models and humans with or without PCOS.

SEARCH METHODS

We searched for articles published in English and Portuguese in PubMed. Keywords were as follows: polycystic ovary syndrome, steroidogenesis, adrenal glands, theca cells, granulosa cells, adipocytes, adipocytokines, obesity, enzyme activation, and cytochrome P450 enzymes. We expanded the search into the references from the retrieved articles.

OUTCOMES

Glucocorticoids and sex-steroids modulate adipocyte differentiation and function. Dysfunctional adipocyte products play important roles in the metabolic and endocrine pathways in animals and women with PCOS. Most adipokines participate in the regulation of the hypothalamic-pituitary-adrenal and ovarian axes. In animal models of PCOS, hyperinsulinemia and poor fertility are common; various adipokines modulate ovarian steroidogenesis, depending on the species. Women with PCOS secrete unbalanced levels of adipocyte products, characterised by higher levels of leptin and lower levels of adiponectin. Leptin expression positively correlates with body mass index, waist/hip ratio and levels of total cholesterol, triglyceride, luteinising hormone, oestradiol and androgens. Leptin inhibits the production of oestradiol and, in granulosa cells, may modulate 17-hydroxylase and aromatase enzyme activities. Adiponectin levels negatively correlate with fat mass, body mass index, waist-hip ratio, glucose, insulin and triglycerides, and decrease androgen production by altering expression of luteinising hormone receptor, steroidogenic acute regulatory protein, cholesterol-side-chain cleavage enzyme and 17-hydroxylase. Resistin expression positively correlates with body mass index and testosterone, and promotes the expression of 17-hydroxylase enzyme in theca cells. The potential benefits of adipokines in the treatment of women with PCOS require more investigation.

WIDER IMPLICATIONS

The current data regarding the relationship between adipocyte products and steroidogenic cells are conflicting in animals and humans. Polycystic ovary syndrome is an excellent model to investigate the interrelationship among adipocyte and steroidogenic cells. Women with PCOS manifest some pathological conditions associated with hyperandrogenism and adipocyte products. In animals, cross-talk between cells may vary according to species, and the current review suggests opportunities to test new medications to prevent or even reverse several harmful sequelae of PCOS in humans. Further studies are required to investigate the possible therapeutic application of adipokines in women with obese and non-obese PCOS. Meanwhile, when appropriate, metformin use alone, or associated with flutamide, may be considered for therapeutic purposes.

Risk of Insulin Resistance and Metabolic Syndrome in Women with Hyperandrogenemia: A Comparison between PCOS Phenotypes and Beyond

Polycystic ovary syndrome (PCOS) is the most common endocrine disorder in premenopausal women, with a wide spectrum of possible phenotypes, symptoms and sequelae according to the current clinical definition. However, there are women who do not fulfill at least two out of the three commonly used "Rotterdam criteria" and their risk of developing type 2 diabetes or obesity later in life is not defined. Therefore, we addressed this important gap by conducting a retrospective analysis based on 750 women with and without PCOS. We compared four different PCOS phenotypes according to the Rotterdam criteria with women who exhibit only one Rotterdam criterion and with healthy controls. Hormone and metabolic differences were assessed by analysis of variance (ANOVA) as well as logistic regression analysis. We found that hyperandrogenic women have per se a higher risk of developing insulin resistance compared to phenotypes without hyperandrogenism and healthy controls. In addition, hyperandrogenemia is associated with developing insulin resistance also in women with no other Rotterdam criterion. Our study encourages further diagnostic and therapeutic approaches for PCOS phenotypes in order to account for varying risks of developing metabolic diseases. Finally, women with hyperandrogenism as the only symptom should also be screened for insulin resistance to avoid later metabolic risks.

Dynamic changes in chromatin accessibility, altered adipogenic gene expression, and total versus de novo fatty acid synthesis in subcutaneous adipose stem cells of normal-weight polycystic ovary syndrome (PCOS) women during adipogenesis: evidence of cellular programming

Background

Normal-weight polycystic ovary syndrome (PCOS) women exhibit adipose resistance in vivo accompanied by enhanced subcutaneous (SC) abdominal adipose stem cell (ASC) development to adipocytes with accelerated lipid accumulation per cell in vitro. The present study examines chromatin accessibility, RNA expression and fatty acid (FA) synthesis during SC abdominal ASC differentiation into adipocytes in vitro of normal-weight PCOS versus age- and body mass index-matched normoandrogenic ovulatory (control) women to study epigenetic/genetic characteristics as well as functional alterations of PCOS and control ASCs during adipogenesis.

Results

SC abdominal ASCs from PCOS women versus controls exhibited dynamic chromatin accessibility during adipogenesis, from significantly less chromatin accessibility at day 0 to greater chromatin accessibility by day 12, with enrichment of binding motifs for transcription factors (TFs) of the AP-1 subfamily at days 0, 3, and 12. In PCOS versus control cells, expression of genes governing adipocyte differentiation (PPARγ, CEBPα, AGPAT2) and function (ADIPOQ, FABP4, LPL, PLIN1, SLC2A4) was increased two–sixfold at days 3, 7, and 12, while that involving Wnt signaling (FZD1, SFRP1, and WNT10B) was decreased. Differential gene expression in PCOS cells at these time points involved triacylglycerol synthesis, lipid oxidation, free fatty acid beta-oxidation, and oxidative phosphorylation of the TCA cycle, with TGFB1 as a significant upstream regulator. There was a broad correspondence between increased chromatin accessibility and increased RNA expression of those 12 genes involved in adipocyte differentiation and function, Wnt signaling, as well as genes involved in the triacylglycerol synthesis functional group at day 12 of adipogenesis. Total content and de novo synthesis of myristic (C14:0), palmitic (C16:0), palmitoleic (C16:1), and oleic (C18:1) acid increased from day 7 to day 12 in all cells, with total content and de novo synthesis of FAs significantly greater in PCOS than controls cells at day 12.

Conclusions

In normal-weight PCOS women, dynamic chromatin remodeling of SC abdominal ASCs during adipogenesis may enhance adipogenic gene expression as a programmed mechanism to promote greater fat storage.

Mechanisms of intergenerational transmission of polycystic ovary syndrome

Developmental origins of adult disease (DoHAD) refers to critical gestational ages during human fetal development and beyond when the endocrine metabolic status of the mother can permanently program the physiology and/or morphology of the fetus, modifying its susceptibility to disease after birth. The aim of this review is to address how DoHAD plays an important role in the phenotypic expression of polycystic ovary syndrome (PCOS), the most common endocrinopathy of women characterized by hyperandrogenism, oligo-anovulation and polycystic ovarian morphology. Clinical studies of PCOS women are integrated with findings from relevant animal models to show how intergenerational transmission of these central components of PCOS are programmed through an altered maternal endocrine-metabolic environment that adversely affects the female fetus and long-term offspring health. Prenatal testosterone treatment in monkeys and sheep have been particularly crucial in our understanding of developmental programming of PCOS because organ system differentiation in these species, as in humans, occurs during fetal life. These animal models, along with altricial rodents, produce permanent PCOS-like phenotypes variably characterized by LH hypersecretion from reduced steroid-negative feedback, hyperandrogenism, ovulatory dysfunction, increased adiposity, impaired glucose-insulin homeostasis and other metabolic abnormalities. The review concludes that DoHAD underlies the phenotypic expression of PCOS through an altered maternal endocrine-metabolic environment that can induce epigenetic modifications of fetal genetic susceptibility to PCOS after birth. It calls for improved maternal endocrine-metabolic health of PCOS women to lower their risks of pregnancy-related complications and to potentially reduce intergenerational susceptibility to PCOS and its metabolic derangements in offspring.

Current concepts of polycystic ovary syndrome pathogenesis

PURPOSE OF REVIEW

This review provides a model for understanding polycystic ovary syndrome (PCOS) pathophysiology and updates the evidence on which it is based. Then, it highlights complimentary molecular genetic and epigenetic advances in understanding PCOS cause.

RECENT FINDINGS

Important studies into PCOS cause built on the 2014 discovery of a novel regulatory protein variant that underlies the typical PCOS steroidogenic abnormalities: DENND1A.V2 (differentially expressed in normal and neoplastic development, isoform 1A, variant 2). Over 30 DENND1A gene variants have been found, the vast majority upstream of the coding sequence and potentially regulatory. These variants are individually uncommon but collectively plausibly cause 50% of PCOS. Anti-Müllerian hormone (AMH)/AMH receptor variants with decreased function possibly cause 6.7% of PCOS. DENNND1A was recently reported to belong to a signaling network that upregulates luteinizing hormone receptor expression and insulin mitogenic signaling. Prenatal androgen administration has proven to be a potent epigenetic regulator that causes transgenerational epigenomic changes in a mouse PCOS model with similarities to those in human PCOS and PCOS daughters.

SUMMARY

In addition to finding how gene variants contribute to PCOS pathogenesis, better understanding of androgen epigenetic mechanisms of action in diverse tissues can be expected to expand our understanding of PCOS pathogenesis.

Endocrine-Metabolic Dysfunction in Polycystic Ovary Syndrome: an Evolutionary Perspective

Polycystic ovary syndrome (PCOS) is characterized by hyperandrogenism, oligo-anovulation and polycystic ovarian morphology, with metabolic dysfunction from insulin resistance and abdominal fat accumulation worsened by obesity. As ancestral traits, these features could have favored abdominal fat deposition for energy use during starvation, but have evolved into different PCOS phenotypes with variable metabolic dysfunction. Adipose dysfunction in PCOS from hyperandrogenemia and hyperinsulinemia likely constrains subcutaneous (SC) fat storage, promoting lipotoxicity through ectopic lipid accumulation and oxidative stress, insulin resistance and inflammation in non-adipose tissue. Recent findings of inherently exaggerated SC abdominal stem cell development to adipocytes in women with PCOS, and PCOS-like traits in adult female monkeys with natural hyperandrogenemia, imply common ancestral origins of PCOS in both human and nonhuman primates.

Precocious subcutaneous abdominal stem cell development to adipocytes in normal-weight women with polycystic ovary syndrome

OBJECTIVE

To examine whether abnormal subcutaneous (SC) abdominal adipose stem cell (ASC) development to adipocytes in polycystic ovary syndrome (PCOS) correlates with hyperandrogenism.

DESIGN

Prospective cohort study.

SETTING

Academic medical center.

PATIENT(S)

Eight normal-weight women with PCOS and eight normoandrogenic ovulatory (control) women matched for age and body mass index.

INTERVENTION(S)

Circulating hormone and metabolic measurements, intravenous glucose tolerance testing, total body dual-energy X-ray absorptiometry, and SC abdominal fat biopsy.

MAIN OUTCOME MEASURE(S)

In vitro ASC commitment to preadipocytes (ZFP423 protein expression, day 0.5), preadipocyte differentiation to adipocytes (PPARγ gene expression, day 3) and adipocyte lipid content (Oil-Red-O fluorescence, day 12) comparisons correlated with clinical outcomes.

RESULT(S)

In women with PCOS, SC abdominal ASCs compared with those of control women showed exaggerated commitment to preadipocytes and had greater lipid content in newly formed adipocytes after in vitro maturation. In all women combined, ZFP423 protein expression negatively correlated with fasting plasma glucose levels whereas the lipid content of newly formed adipocytes positively correlated with both PPARγ gene expression and serum free testosterone levels.

CONCLUSION(S)

In normal-weight women with PCOS compared with the control group, exaggerated SC abdominal ASC commitment to preadipocytes and enhanced adipocyte lipid content during maturation in vitro negatively and positively correlate with circulating fasting glucose and androgen levels, respectively, as a possible mechanism to maintain glucose-insulin homeostasis when fat accretion is accelerated.

Metabolic Effects of Testosterone Hormone Therapy in Normal and Orchiectomized Male Rats: From Indirect Calorimetry to Lipolytic Enzymes

BACKGROUND AND AIM

Changes in total energy expenditure (TEE) and substrate metabolism may help explain the metabolic actions of testosterone (T). This study measured respiratory quotient (RQ), TEE, ghrelin, insulin, and key lipolysis enzyme concentrations in relation to body weight (wt) and food intake (FI) in both normal and bilaterally orchiectomized rats with/without T treatment.

METHODS

In total, thirty-two male Wistar rats (300-400 g) were divided into four groups (n = 8/group), including (a) sham-operated and vehicle-injected group (Sham), (b) T-treated sham group (T-Sham) for which sham-operated rats were injected with IM testosterone undecanoate (100 mg/kg, for one week), (c) orchiectomy and vehicle-injected group (Orch), and (d) T-replaced orchiectomy group (T-Orch). After one week, FI and wt were automatically recorded, indirect calorimetry parameters were measured, and blood samples were collected to measure T, ghrelin, insulin, growth hormone (GH), glucose, hormone-sensitive lipase (HSL), adipocyte triglyceride lipase (ATGL), free fatty acids (FFA), and lipid profiles.

RESULTS

Orchiectomy decreased ghrelin, GH, and insulin levels, increased TEE and RQ, and lowered FI and wt. The T-Orch group exhibited increased levels of ghrelin (3-fold), insulin, GH, blood levels of lipolysis products, TEE, and FI in addition to reduced glucose levels (P < 0.05). This group demonstrated no significant changes in wt. In the T-Sham group, T increased ghrelin and insulin levels (P < 0.05) with strong positive correlations (r = 0.663 and 0.644, respectively, P < 0.05), increased ATGL levels, RQ toward carbohydrate utilization ranges, and TEE, and reduced HSL levels (P < 0.05) with insignificant changes in FI or wt.

CONCLUSIONS

T administration in orchiectomized rats significantly increased orexigenic mediators such as ghrelin and insulin without inducing any significant changes in wt. The mechanism for this finding might be the increased TEE and the stimulation of lipolysis through the ATGL enzyme. The associated rise of GH might help in interference with accumulation of lipid in adipose tissue. Apart from the effect on GH, T-Sham showed similar effects of T supplementation.

Intrinsic and Extrinsic Thymic Adrenergic Networks: Sex Steroid-Dependent Plasticity

The thymus is sexually differentiated organ providing microenvironment for T-cell precursor differentiation/maturation in the major histocompatibility complex-restricted self-tolerant T cells. With increasing age, the thymus undergoes involution leading to the decline in efficacy of thymopoiesis. Noradrenaline from thymic nerve fibers and "(nor)adrenergic" cells is involved in the regulation of thymopoiesis. In rodents, noradrenaline concentration in thymus and adrenoceptor (AR) expression on thymic cells depend on sex and age. These differences are suggested to be implicated in the development of sexual diergism and the age-related decline in thymopoiesis. The programming of both thymic sexual differentiation and its involution occurs during the critical early perinatal period and may be reprogrammed during peripubertal development. The thymic (re)programming is critically dependent on circulating levels of gonadal steroids. Although the underlying molecular mechanisms have not yet been elucidated fully, it is assumed that the gonadal steroid action during the critical perinatal/peripubertal developmental periods leads to long-lasting changes in the efficacy of thymopoiesis partly through (re)programming of "(nor)adrenergic" cell networks and AR expression on thymic cells.

Discovery of Novel Lipid Profiles in PCOS: Do Insulin and Androgen Oppositely Regulate Bioactive Lipid Production?

CONTEXT

Polycystic ovary syndrome (PCOS) is a complex syndrome showing clinical features of an endocrine/metabolic disorder, including hyperinsulinemia and hyperandrogenism. Polyunsaturated fatty acids (PUFAs) and their derivatives, both tightly linked to PCOS and obesity, play important roles in inflammation and reproduction.

OBJECTIVE

This study aimed to investigate serum lipid profiles in newly diagnosed patients with PCOS using lipidomics and correlate these features with the hyperinsulinemia and hyperandrogenism associated with PCOS and obesity.

DESIGN AND SETTING

Thirty-two newly diagnosed women with PCOS and 34 controls were divided into obese and lean subgroups. A PCOS rat model was used to validate results of the human studies.

MAIN OUTCOME MEASURES

Serum lipid profiles, including phospholipids, free fatty acids (FFAs), and bioactive lipids, were analyzed using gas chromatography-mass spectrometry (MS) and liquid chromatography-MS.

RESULTS

Elevation in phosphatidylcholine and a concomitant decrease in lysophospholipid were found in obese patients with PCOS vs lean controls. Obese patients with PCOS had decreased PUFA levels and increased levels of long-chain saturated fatty acids vs lean controls. Serum bioactive lipids downstream of arachidonic acid were increased in obese controls, but reduced in both obese and lean patients with PCOS vs their respective controls.

CONCLUSIONS

Patients with PCOS showed abnormal levels of phosphatidylcholine, FFAs, and PUFA metabolites. Circulating insulin and androgens may have opposing effects on lipid profiles in patients with PCOS, particularly on the bioactive lipid metabolites derived from PUFAs. These clinical observations warrant further studies of the molecular mechanisms and clinical implications of PCOS and obesity.

The Pathogenesis of Polycystic Ovary Syndrome (PCOS): The Hypothesis of PCOS as Functional Ovarian Hyperandrogenism Revisited

Polycystic ovary syndrome (PCOS) was hypothesized to result from functional ovarian hyperandrogenism (FOH) due to dysregulation of androgen secretion in 1989-1995. Subsequent studies have supported and amplified this hypothesis. When defined as otherwise unexplained hyperandrogenic oligoanovulation, two-thirds of PCOS cases have functionally typical FOH, characterized by 17-hydroxyprogesterone hyperresponsiveness to gonadotropin stimulation. Two-thirds of the remaining PCOS have FOH detectable by testosterone elevation after suppression of adrenal androgen production. About 3% of PCOS have a related isolated functional adrenal hyperandrogenism. The remaining PCOS cases are mild and lack evidence of steroid secretory abnormalities; most of these are obese, which we postulate to account for their atypical PCOS. Approximately half of normal women with polycystic ovarian morphology (PCOM) have subclinical FOH-related steroidogenic defects. Theca cells from polycystic ovaries of classic PCOS patients in long-term culture have an intrinsic steroidogenic dysregulation that can account for the steroidogenic abnormalities typical of FOH. These cells overexpress most steroidogenic enzymes, particularly cytochrome P450c17. Overexpression of a protein identified by genome-wide association screening, differentially expressed in normal and neoplastic development 1A.V2, in normal theca cells has reproduced this PCOS phenotype in vitro. A metabolic syndrome of obesity-related and/or intrinsic insulin resistance occurs in about half of PCOS patients, and the compensatory hyperinsulinism has tissue-selective effects, which include aggravation of hyperandrogenism. PCOS seems to arise as a complex trait that results from the interaction of diverse genetic and environmental factors. Heritable factors include PCOM, hyperandrogenemia, insulin resistance, and insulin secretory defects. Environmental factors include prenatal androgen exposure and poor fetal growth, whereas acquired obesity is a major postnatal factor. The variety of pathways involved and lack of a common thread attests to the multifactorial nature and heterogeneity of the syndrome. Further research into the fundamental basis of the disorder will be necessary to optimally correct androgen levels, ovulation, and metabolic homeostasis.

Testosterone inhibits expression of lipogenic genes in visceral fat by an estrogen-dependent mechanism

The influence of the aromatase enzyme on the chronic fat-sparing effects of testosterone requires further elucidation. Our purpose was to determine whether chronic anastrozole (AN, an aromatase inhibitor) treatment alters testosterone-mediated lipolytic/lipogenic gene expression in visceral fat. Ten-month-old Fischer 344 rats (n = 6/group) were subjected to sham surgery (SHAM), orchiectomy (ORX), ORX + treatment with testosterone enanthate (TEST, 7.0 mg/wk), or ORX + TEST + AN (0.5 mg/day), with drug treatment beginning 14 days postsurgery. At day 42, ORX animals exhibited nearly undetectable serum testosterone and 29% higher retroperitoneal fat mass than SHAM animals (P < 0.001). TEST produced a ∼380-415% higher serum testosterone than SHAM (P < 0.001) and completely prevented ORX-induced visceral fat gain (P < 0.001). Retroperitoneal fat was 21% and 16% lower in ORX + TEST than SHAM (P < 0.001) and ORX + TEST + AN (P = 0.007) animals, while serum estradiol (E₂) was 62% (P = 0.024) and 87% (P = 0.010) higher, respectively. ORX stimulated lipogenic-related gene expression in visceral fat, demonstrated by ∼84-154% higher sterol regulatory element-binding protein-1 (SREBP-1, P = 0.023), fatty acid synthase (P = 0.01), and LPL (P < 0.001) mRNA than SHAM animals, effects that were completely prevented in ORX + TEST animals (P < 0.01 vs. ORX for all). Fatty acid synthase (P = 0.061, trend) and LPL (P = 0.043) mRNA levels were lower in ORX + TEST + AN than ORX animals and not different from SHAM animals but remained higher than in ORX + TEST animals (P < 0.05). In contrast, the ORX-induced elevation in SREBP-1 mRNA was not prevented by TEST + AN, with SREBP-1 expression remaining ∼117-171% higher than in SHAM and ORX + TEST animals (P < 0.01). Across groups, visceral fat mass and lipogenic-related gene expression were negatively associated with serum testosterone, but not E₂ Aromatase inhibition constrains testosterone-induced visceral fat loss and the downregulation of key lipogenic genes at the mRNA level, indicating that E₂ influences the visceral fat-sparing effects of testosterone.

Western-style diet, sex steroids and metabolism

The evolutionary transition from hunting to farming was associated with introduction of carbohydrate-rich diets. Today, the increased consumption of simple sugars and high-fat food brought about by Western-style diet and physical inactivity are leading causes of the growing obesity epidemic in the Western society. The extension of human lifespan far beyond reproductive age increased the burden of metabolic disorders associated with overnutrition and age-related hypogonadism. Sex steroids are essential regulators of both reproductive function and energy metabolism, whereas their imbalance causes infertility, obesity, glucose intolerance, dyslipidemia, and increased appetite. Clinical and translational studies suggest that dietary restriction and weight control can improve metabolic and reproductive outcomes of sex hormone-related pathologies, including testosterone deficiency in men and natural menopause and hyperandrogenemia in women. Minimizing metabolic and reproductive decline through rationally designed diet and exercise can help extend human reproductive age and promote healthy aging. This article is part of a Special Issue entitled: Oxidative Stress and Mitochondrial Quality in Diabetes/Obesity and Critical Illness Spectrum of Diseases - edited by P. Hemachandra Reddy.

Characteristics of metabolic changes in adipocytes of growing rats

Adipocytes, cells of white fat tissue, store energy in the form of lipids and have also endocrine functions. Disturbances in adipocyte metabolism lead to decreased or excessive fat tissue accumulation and are associated with numerous diseases. Pathologic alterations in adipose tissue are known to develop with age, however, changes in young, growing subjects are poorly elucidated. In the present study, glucose transport and metabolism, hyperpolarization of the inner mitochondrial membrane and the lipolytic activity were compared in the epididymal adipocytes of 8-week-old and 16-week-old rats. It was demonstrated that glucose conversion to lipids, glucose transport and oxidation was decreased in the adipocytes of the older animals. These effects were accompanied by increase in lactate release and by decrease in hyperpolarization of the mitochondrial membrane. Lipolytic response to epinephrine was increased (at lower concentrations of the hormone) or reduced (at higher concentration) in the adipocytes of the older rats. However, induction of lipolysis by the direct activation of protein kinase A induced similar response. It was also demonstrated that inhibition of phosphodiesterase 3B or adenosine A1 receptor blocking caused lower lipolysis in the cells of the older rats. Moreover, antilipolytic action of insulin was impaired in the adipocytes of these rats, probably due to changes in the initial steps of the insulin signaling pathway. However, the use of the pharmacologic inhibitor of protein kinase A instead of insulin resulted in similar antilipolysis in both groups of cells. These results show that, in spite of relatively small age difference, substantial changes in adipose tissue metabolism develop in these animals. Decreased response to insulin action seems to be particularly relevant finding.

Changes of Serum Adiponectin and Testosterone Concentrations Following Twelve Weeks Resistance Training in Obese Young Men

Background:

Circulating levels of adiponectin and testosterone decrease in obese men and this increases risks of cardiovascular disease and diabetes.

Objectives:

The purpose of this study was to survey changes of serum adiponectin and testosterone concentrations following twelve weeks resistance training in obese young men.

Patients and Methods:

In a semi-experimental study, twenty one obese young men were randomly placed in two groups: resistance training (26.5 ± 2.8 years) and control (27.4 ± 2.9 years). General characteristics of subjects and serum levels of adiponectin and testosterone were assessed before and after training. Resistance training protocol consisted of twelve weeks weight training (3 sessions per week, 10 exercises, 3 sets of 8 - 12 repetitions in each exercise, intensity 60% - 80% of one repetition maximum, rest between sets 1 minute and between exercises 2 minutes, duration of main training 20 - 40 minutes per each session).

Results:

Resistance training had no significant effect on body weight and body mass index (P > 0.05), whereas it decreased body fat percent (P = 0.017). Also, serum adiponectin (8.1 ± 1.8 vs. 10.5 ± 2.3 μg/mL) and testosterone concentrations (6.9 ± 2.4 vs. 8.2 ± 1.7 ng/mL) were increased after resistance training (P = 0.033, P = 0.018 respectively), while there were no significant changes in serum levels of these hormones in control group (P > 0.05).

Conclusions:

Twelve weeks of resistance training increased serum concentrations of adiponectin and testosterone in obese young men. With respect to inverse associations between changes of adiponectin and testosterone with BFP and insulin level variations after resistance training, it is recommended that obese young men do resistance training to benefit useful decreasing/preventive effects of this type of training against the risks of cardiovascular diseases and diabetes.

Potential effects of aerobic exercise on the expression of perilipin 3 in the adipose tissue of women with polycystic ovary syndrome: a pilot study

OBJECTIVE

Polycystic ovary syndrome (PCOS) is associated with reduced adipose tissue lipolysis that can be rescued by aerobic exercise. We aimed to identify differences in the gene expression of perilipins and associated targets in adipose tissue in women with PCOS before and after exercise.

DESIGN AND METHODS

We conducted a cross-sectional study in eight women with PCOS and eight women matched for BMI and age with normal cycles. Women with PCOS also completed a 16-week prospective aerobic exercise-training study. Abdominal subcutaneous adipose tissue biopsies were collected, and primary adipose-derived stromal/stem cell cultures were established from women with PCOS before 16 weeks of aerobic exercise training (n=5) and controls (n=5). Gene expression was measured using real-time PCR, in vitro lipolysis was measured using radiolabeled oleate, and perilipin 3 (PLIN3) protein content was measured by western blotting analysis.

RESULTS

The expression of PLIN1, PLIN3, and PLIN5, along with coatomers ARF1, ARFRP1, and βCOP was ∼ 80% lower in women with PCOS (all P<0.05). Following exercise training, PLIN3 was the only perilipin to increase significantly (P<0.05), along with coatomers ARF1, ARFRP1, βCOP, and SEC23A (all P<0.05). Furthermore, PLIN3 protein expression was undetectable in the cell cultures from women with PCOS vs controls. Following exercise training, in vitro adipose oleate oxidation, glycerol secretion, and PLIN3 protein expression were increased, along with reductions in triglyceride content and absence of large lipid droplet morphology.

CONCLUSIONS

These findings suggest that PLIN3 and coatomer GTPases are important regulators of lipolysis and triglyceride storage in the adipose tissue of women with PCOS.

Adiposity and metabolic dysfunction in polycystic ovary syndrome

Polycystic ovary syndrome (PCOS) is the most common hormonal disorder among reproductive-age women and is associated with a high risk for metabolic disorders. Adiposity and insulin resistance are two prevalent conditions in PCOS and the likely culprits for the heightened metabolic risk. Up to 60% of women with PCOS are considered to be overweight or obese, and even among non-obese women with PCOS there is an increased accumulation of adipose tissue in abdominal depots. Insulin resistance in PCOS is unique and independent of obesity, as even non-obese women with this condition are frequently insulin resistant. However, obesity substantially aggravates the insulin resistance and the metabolic and reproductive abnormalities in women with PCOS. Recently, it has been shown that many aspects of adipose tissue function in PCOS are abnormal, and these abnormalities likely predispose to development of insulin resistance even in the absence of obesity. This review provides an overview of these abnormalities and their impact on development of metabolic disorders. At the end, an overview of the therapeutic options for management of adiposity and its complications in PCOS are discussed.

The Role of Metformin in Metabolic Disturbances during Pregnancy: Polycystic Ovary Syndrome and Gestational Diabetes Mellitus

Maintenance of gestation implicates complex function of multiple endocrine mechanisms, and disruptions of the global metabolic environment prompt profound consequences on fetomaternal well-being during pregnancy and postpartum. Polycystic Ovary Syndrome (PCOS) and gestational diabetes mellitus (GDM) are very frequent conditions which increase risk for pregnancy complications, including early pregnancy loss, pregnancy-induced hypertensive disorders, and preterm labor, among many others. Insulin resistance (IR) plays a pivotal role in the pathogenesis of both PCOS and GDM, representing an important therapeutic target, with metformin being the most widely prescribed insulin-sensitizing antidiabetic drug. Although traditional views neglect use of oral antidiabetic agents during pregnancy, increasing evidence of safety during gestation has led to metformin now being recognized as a valuable tool in prevention of IR-related pregnancy complications and management of GDM. Metformin has been demonstrated to reduce rates of early pregnancy loss and onset of GDM in women with PCOS, and it appears to offer better metabolic control than insulin and other oral antidiabetic drugs during pregnancy. This review aims to summarize key aspects of current evidence concerning molecular and epidemiological knowledge on metformin use during pregnancy in the setting of PCOS and GDM.

Adrenergic control of lipolysis in women compared with men

Data suggest women are more sensitive to the lipolytic action of epinephrine compared with men while maintaining similar glucoregulatory effects (Horton et al. J Appl Physiol 107: 200-210, 2009). This study aimed to determine the specific adrenergic receptor(s) that may mediate these sex differences. Lean women (n = 14) and men (n = 16) were studied on 4 nonconsecutive days during the following treatment infusions: saline (S: control), epinephrine [E: mixed β-adrenergic (lipolytic) and α2-adrenergic (antilipolytic) stimulation], epinephrine + phentolamine (E + P: mixed β-adrenergic stimulation only), and terbutaline (T: selective β2-adrenergic stimulation). Tracer infusions of glycerol, palmitate, and glucose were administered to determine systemic lipolysis, free fatty acid (FFA) release, and glucose turnover, respectively. Following basal measurements, substrate and hormone concentrations were measured in all subjects over 90 min of treatment and tracer infusion. Women had greater increases in glycerol and FFA concentrations with all three hormone infusions compared with men (P < 0.01). Glycerol and palmitate rate of appearance (Ra) and rate of disappearance (Rd) per kilogram body weight were greater with E infusion in women compared with men (P < 0.05), whereas no sex differences were observed with other treatments. Glucose concentration and kinetics were not different between sexes with any infusion. In conclusion, these data support the hypothesis that the greater rate of lipolysis in women with infusion of E was likely due to lesser α2 antilipolytic activation. These findings may help explain why women have greater lipolysis and fat oxidation during exercise, a time when epinephrine concentration is elevated.

Exaggerated activity of HPA axis in obese rats fed normocaloric liquid nutrition

Experimental and clinical studies have shown alterations in activity of systems responsible for neuroendocrine stress response in obese individuals. Therefore we investigated the effect of palatable normocaloric liquid nutrition (Fresubin) on alterations in activity of the hypothalamic-pituitary-adrenal (HPA) axis in male Wistar rats of different developmental stages. Control rats (CON) received standard pellet chow all the time from weaning (21st day of age) to 150 days. Fresubin was administered throughout the experiment (LN), only in juvenility (from 21st to 90th day of age; LNJ) or only in adulthood (from 90th to 150th day of age; LNA). Body weight and energy intake were periodically monitored. Adrenal gland and fat tissue weight and plasma corticosterone levels (CORT) was determined after sacrification. Fresubin intake induced obesity in LN and LNA rats. In LN and LNA rats were observed elevated serum CORT levels, but only in LN rats with significant twofold increase compared to LNJ rats. However, the weight of adrenal glands did not differ between LN, LNJ and LNA experimental groups. Based on our results, we suggest, that obesity induced by Fresubin in LN and LNA rats is accompanied by increased HPA activity represented by elevated plasma CORT levels in these rats.

Gene expression in subcutaneous adipose tissue differs in women with polycystic ovary syndrome and controls matched pair-wise for age, body weight, and body mass index

Adipose tissue dysfunction may be a central factor in the pathogenesis of insulin resistance in women with polycystic ovary syndrome (PCOS). Gene expression in subcutaneous adipose tissue in PCOS and its relation to metabolic and endocrine features of the syndrome have been fragmentarily investigated. The aim was to assess in subcutaneous adipose tissue the expression of genes potentially associated with adipose tissue dysfunction and to explore their relation to features of the syndrome. Twenty-one women with PCOS (body mass index [BMI] 18.2–33.4 kg/m²) and 21 controls (BMI 19.2–31.7 kg/m²) were matched pair-wise for age, body weight, and BMI. Tissue biopsies were obtained to measure mRNA expression of 44 genes (TaqMan Low Density Array). Differential expression levels were correlated with BMI, glucose infusion rate (GIR), sex hormone binding globulin (SHBG), and sex steroids. In PCOS, expression of adiponectin receptor 2 (ADIPOR2), LPL, and twist-related protein 1 (TWIST1) was decreased, while expression of chemokine (C-C motif) ligand 2 (CCL2) and heme oxygenase (decycling 1) (HMOX1) was increased. TWIST1 and HMOX1, both novel adipokines, correlated with BMI and GIR. After BMI adjustment, LPL and ADIPOR2 expression correlated with plasma estradiol, and CCL2 expression correlated with GIR, in all women. We conclude that adipose tissue mRNA expression differed in PCOS women and controls and that two novel adipokines, TWIST1 and HMOX1, together with adiponectin, LPL, and CCL2, and their downstream pathways merit further investigation.

Regulation of adipocyte lipolysis

In adipocytes the hydrolysis of TAG to produce fatty acids and glycerol under fasting conditions or times of elevated energy demands is tightly regulated by neuroendocrine signals, resulting in the activation of lipolytic enzymes. Among the classic regulators of lipolysis, adrenergic stimulation and the insulin-mediated control of lipid mobilisation are the best known. Initially, hormone-sensitive lipase (HSL) was thought to be the rate-limiting enzyme of the first lipolytic step, while we now know that adipocyte TAG lipase is the key enzyme for lipolysis initiation. Pivotal, previously unsuspected components have also been identified at the protective interface of the lipid droplet surface and in the signalling pathways that control lipolysis. Perilipin, comparative gene identification-58 (CGI-58) and other proteins of the lipid droplet surface are currently known to be key regulators of the lipolytic machinery, protecting or exposing the TAG core of the droplet to lipases. The neuroendocrine control of lipolysis is prototypically exerted by catecholaminergic stimulation and insulin-induced suppression, both of which affect cyclic AMP levels and hence the protein kinase A-mediated phosphorylation of HSL and perilipin. Interestingly, in recent decades adipose tissue has been shown to secrete a large number of adipokines, which exert direct effects on lipolysis, while adipocytes reportedly express a wide range of receptors for signals involved in lipid mobilisation. Recently recognised mediators of lipolysis include some adipokines, structural membrane proteins, atrial natriuretic peptides, AMP-activated protein kinase and mitogen-activated protein kinase. Lipolysis needs to be reanalysed from the broader perspective of its specific physiological or pathological context since basal or stimulated lipolytic rates occur under diverse conditions and by different mechanisms.

Transcriptomic profiling as a screening tool to detect trenbolone treatment in beef cattle

The effects of steroid hormone implants containing trenbolone alone (Finaplix-H), combined with 17β-oestradiol (17β-E; Revalor-H), or with 17β-E and dexamethasone (Revalor-H plus dexamethasone per os) on the bovine muscle transcriptome were examined by DNA-microarray. Overall, large sets of genes were shown to be modulated by the different growth promoters (GPs) and the regulated pathways and biological processes were mostly shared among the treatment groups. Using the Prediction Analysis of Microarray program, GP-treated animals were accurately identified by a small number of predictive genes. A meta-analysis approach was also carried out for the Revalor group to potentially increase the robustness of class prediction analysis. After data pre-processing, a high level of accuracy (90%) was obtained in the classification of samples, using 105 predictive gene markers. Transcriptomics could thus help in the identification of indirect biomarkers for anabolic treatment in beef cattle to be applied for the screening of muscle samples collected after slaughtering.

Increasing the Number of Unloading/Reambulation Cycles does not Adversely Impact Body Composition and Lumbar Bone Mineral Density but Reduces Tissue Sensitivity

A single exposure to hindlimb unloading leads to changes in body mass, body composition and bone, but the consequences of multiple exposures are not yet understood. Within a 18wk period, adult C57BL/6 male mice were exposed to one (1x-HLU), two (2x-HLU) or three (3x-HLU) cycles of 2 wk of hindlimb unloading (HLU) followed by 4 wk of reambulation (RA), or served as ambulatory age-matched controls. In vivo µCT longitudinally tracked changes in abdominal adipose and lean tissues, lumbar vertebral apparent volumetric bone mineral density (vBMD) and upper hindlimb muscle cross-sectional area before and after the final HLU and RA cycle. Significant decreases in total adipose tissue and vertebral vBMD were observed such that all unloaded animals reached similar values after the final unloading cycle. However, the magnitude of these losses diminished in mice undergoing their 2^nd or 3^rd HLU cycle. Irrespective of the number of HLU/RA cycles, total adipose tissue and vertebral vBMD recovered and were no different from age-matched controls after the final RA period. In contrast, upper hindlimb muscle cross-sectional area was significantly lower than controls in all unloaded groups after the final RA period. These results suggest that tissues in the abdominal region are more resilient to multiple bouts of unloading and more amenable to recovery during reambulation than the peripheral musculoskeletal system.

Insulin resistance and the polycystic ovary syndrome revisited: an update on mechanisms and implications

Polycystic ovary syndrome (PCOS) is now recognized as an important metabolic as well as reproductive disorder conferring substantially increased risk for type 2 diabetes. Affected women have marked insulin resistance, independent of obesity. This article summarizes the state of the science since we last reviewed the field in the Endocrine Reviews in 1997. There is general agreement that obese women with PCOS are insulin resistant, but some groups of lean affected women may have normal insulin sensitivity. There is a post-binding defect in receptor signaling likely due to increased receptor and insulin receptor substrate-1 serine phosphorylation that selectively affects metabolic but not mitogenic pathways in classic insulin target tissues and in the ovary. Constitutive activation of serine kinases in the MAPK-ERK pathway may contribute to resistance to insulin's metabolic actions in skeletal muscle. Insulin functions as a co-gonadotropin through its cognate receptor to modulate ovarian steroidogenesis. Genetic disruption of insulin signaling in the brain has indicated that this pathway is important for ovulation and body weight regulation. These insights have been directly translated into a novel therapy for PCOS with insulin-sensitizing drugs. Furthermore, androgens contribute to insulin resistance in PCOS. PCOS may also have developmental origins due to androgen exposure at critical periods or to intrauterine growth restriction. PCOS is a complex genetic disease, and first-degree relatives have reproductive and metabolic phenotypes. Several PCOS genetic susceptibility loci have been mapped and replicated. Some of the same susceptibility genes contribute to disease risk in Chinese and European PCOS populations, suggesting that PCOS is an ancient trait.

Role of gonadal hormones in programming developmental changes in thymopoietic efficiency and sexual diergism in thymopoiesis

There is a growing body of evidence indicating the important role of the neonatal steroid milieu in programming sexually diergic changes in thymopoietic efficiency, which in rodents occur around puberty and lead to a substantial phenotypic and functional remodeling of the peripheral T-cell compartment. This in turn leads to an alteration in the susceptibility to infection and various immunologically mediated pathologies. Our laboratory has explored interdependence in the programming and development of the hypothalamo-pituitary-gonadal axis and thymus using experimental model of neonatal androgenization. We have outlined critical points in the complex process of T-cell development depending on neonatal androgen imprinting and the peripheral outcome of these changes and have pointed to underlying mechanisms. Our research has particularly contributed to an understanding of the putative role of changes in catecholamine-mediated communications in the thymopoietic alterations in adult neonatally androgenized rats.

Androgen effects on adipose tissue architecture and function in nonhuman primates

The differential association of hypoandrogenism in men and hyperandrogenism in women with insulin resistance and obesity suggests that androgens may exert sex-specific effects on adipose and other tissues, although the underlying mechanisms remain poorly understood. Moreover, recent studies also suggest that rodents and humans may respond differently to androgen imbalance. To achieve better insight into clinically relevant sex-specific mechanisms of androgen action, we used nonhuman primates to investigate the direct effects of gonadectomy and hormone replacement on white adipose tissue. We also employed a novel ex vivo approach that provides a convenient framework for understanding of adipose tissue physiology under a controlled tissue culture environment. In vivo androgen deprivation of males did not result in overt obesity or insulin resistance but did induce the appearance of very small, multilocular white adipocytes. Testosterone replacement restored normal cell size and a unilocular phenotype and stimulated adipogenic gene transcription and improved insulin sensitivity of male adipose tissue. Ex vivo studies demonstrated sex-specific effects of androgens on adipocyte function. Female adipose tissue treated with androgens displayed elevated basal but reduced insulin-dependent fatty acid uptake. Androgen-stimulated basal uptake was greater in adipose tissue of ovariectomized females than in adipose tissue of intact females and ovariectomized females replaced with estrogen and progesterone in vivo. Collectively, these data demonstrate that androgens are essential for normal adipogenesis in males and can impair essential adipocyte functions in females, thus strengthening the experimental basis for sex-specific effects of androgens in adipose tissue.

Isoflavones as a smart curer for non-alcoholic fatty liver disease and pathological adiposity via ChREBP and Wnt signaling

OBJECTIVE

Non-alcoholic fatty liver disease (NAFLD) and pathological adiposity has emerged as an important modern disease. Along with this, the requirement for alternative and natural medicine for preventing NAFLD and adiposity has been increasing rapidly and considerably. In this report, we will review the biological effect and mechanisms of soy isoflavones on NAFLD and pathologic adiposity mainly through the novel pathways, de novo lipogenic carbohydrate responsive element binding protein (ChREBP) and anti-adipogenic Wnt signaling.

METHODS

This paper reviews in vitro and in vivo isoflavone studies published in 2002 to 2011 in North America and East Asia.

RESULTS

Collectively, the data support a beneficial relation of isoflavones and NAFLD and/or adiposity. Isoflavones suppress ChREBP signaling via protein kinase A (PKA) and/or 5'-AMP activated protein kinase (AMPK)-dependent phosphorylation, which prevents ChREBP from binding to the promoter regions of lipogenic enzyme. Furthermore, isoflavones directly stimulate Wnt signaling via estrogen receptors-dependent pathway, which inactivates glycogen synthase kinase-3 beta (GSK-3β), transactivate T-cell factor/lymphoid-enhancer factor (TCF/LEF), the effector of Wnt signaling, degrade adipogenic peroxisome proliferator-activated receptor γ (PPARγ), augment p300/CBP, the transcriptional co-activators of TCF/LEF.

CONCLUSIONS

Natural compound isoflavones may be useful alternative medicines in preventing NAFLD and pathological adiposity and this action may be partially associated with ChREBP and Wnt signaling.

Neonatal androgenization affects the efficiency of β-adrenoceptor-mediated modulation of thymopoiesis

We tested the hypothesis that neonatal androgenization affects the efficacy of β-adrenoceptor (β-AR)-mediated fine tuning of thymopoiesis in adult female rats by modulating the thymic noradrenaline (NA) level and/or β-AR expression. In adult rats administered with 1000 μg testosterone enanthate at postnatal day 2 a higher density of catecholamine (CA)-synthesizing thymic cells, including thymocytes, and a rise in their CA content was found. In addition, in these animals increased thymic noradrenergic nerve fiber fluorescence intensity, reflecting their increased CA content, was detected. These changes were followed by an increase in thymic NA concentration. The rise in thymic NA content in thymic nerve fibers and cells was associated with changes in the expression of mRNA for enzymes controlling pivotal steps in NA biosynthesis (tyrosine hydroxylase, dopamine-β-hydroxylase) and inactivation (monoamine oxidase). In contrast, the thymic level of β(2)-AR mRNA on a per cell basis and the receptor surface density on thymocytes was reduced in testosterone-treated (TT) rats. As a consequence, 14-day-long treatment with propranolol, a β-AR blocker, was ineffective in modulating T-cell differentiation/maturation in TT rats. In conclusion, the study indicates the importance of the neonatal sex steroid milieu for shaping the immunomodulatory capacity of the thymic NA/β-AR signaling system in adult rats.

Several agents and pathways regulate lipolysis in adipocytes

Adipose tissue is the only tissue capable of hydrolyzing its stores of triacylglycerol (TAG) and of mobilizing fatty acids and glycerol in the bloodstream so that they can be used by other tissues. The full hydrolysis of TAG depends on the activity of three enzymes, adipose triglyceride lipase (ATGL), hormone-sensitive lipase (HSL) and monoacylglycerol lipase, each of which possesses a distinct regulatory mechanism. Although more is known about HSL than about the other two enzymes, it has recently been shown that HLS and ATGL can be activated simultaneously, such that the mechanism that enables HSL to access the surface of lipid droplets also permits the stimulation of ATGL. The classical pathway of lipolysis activation in adipocytes is cAMP-dependent. The production of cAMP is modulated by G-protein-coupled receptors of the Gs/Gi family and cAMP degradation is regulated by phosphodiesterase. However, other pathways that activate TAG hydrolysis are currently under investigation. Lipolysis can also be started by G-protein-coupled receptors of the Gq family, through molecular mechanisms that involve phospholipase C, calmodulin and protein kinase C. There is also evidence that increased lipolytic activity in adipocytes occurs after stimulation of the mitogen-activated protein kinase pathway or after cGMP accumulation and activation of protein kinase G. Several agents contribute to the control of lipolysis in adipocytes by modulating the activity of HSL and ATGL. In this review, we have summarized the signalling pathways activated by several agents involved in the regulation of TAG hydrolysis in adipocytes.

Polycystic ovary syndrome in the pediatric population

Polycystic ovary syndrome (PCOS) is a common disorder characterized by hyperandrogenism and disordered gonadotropin secretion, often associated with insulin resistance. The syndrome, which modulates both hormonal and metabolic processes, is the most common endocrinopathy in reproductive-age women and increases a woman's risk of infertility, endometrial pathology, and cardiometabolic disease. As it is currently defined, PCOS most likely encompasses several distinct diseases with similar clinical phenotypes but different underlying pathophysiological processes. However, hyperandrogenism remains the syndrome's clinical hallmark. The clinical manifestations of PCOS often emerge during childhood or in the peripubertal years, suggesting that the syndrome is influenced by fetal programming and/or early postnatal events. However, given that the full clinical spectrum of PCOS does not typically appear until puberty, a "two-hit" hypothesis has been proposed: (1) a girl develops hyperandrogenism via one or more of many different potential mechanisms; (2) the preexisting hyperandrogenism subsequently disturbs the hypothalamic–pituitary–ovarian axis, resulting in ovulatory dysfunction and sustained hyperandrogenism. No consensus guidelines exist regarding the diagnosis and management of PCOS in the pediatric population; however, because the syndrome is a diagnosis of exclusion, the clinical evaluation of girls suspected of having PCOS is aimed at excluding other causes of androgen excess and menstrual dysfunction. For the syndrome's management, emphasis is placed on lifestyle and symptom-directed treatment.

Genistein and daidzein repress adipogenic differentiation of human adipose tissue-derived mesenchymal stem cells via Wnt/β-catenin signalling or lipolysis

OBJECTIVES

One aspect of the effects of isoflavones against fat deposition might be at least associated with the mechanism by which Wnt/β-catenin signalling inhibits adipocyte differentiation. However, it remains completely unknown as to whether isoflavones might influence Wnt signalling during commitment of pluripotent mesenchymal stem cells (MSCs) to adipose lineages. In the present study, we have investigated the mechanisms underlying effects of genistein and daidzein, the major soy isoflavones, on anti-adipogenic Wnt/β-catenin signalling.

MATERIALS AND METHODS

Adipose tissue-derived (AD) MSCs were exposed continuously to genistein and daidzein (0.01-100 μm) during adipogenic differentiation (21 days). An oestrogen antagonist, ICI 182,780, was used to determine whether or not the isoflavones activated Wnt signalling via oestrogen receptors (ERs).

RESULTS

Genistein and daidzein suppressed adipogenic differentiation of AD-MSCs in a dose-dependent manner and inhibited expression of adipogenic markers, PPARγ, SREBP-1c and Glut 4, from mid-phase differentiation. Microarrays showed that anti-adipogenic effects of genistein were principally attributable to activation of Wnt signalling via ERs-dependent pathway, such as Erk/JNK signalling and LEF/TCF4 co-activators. These findings were supported by evidence that the effects of genistein were offset by ICI182,780. Unlike genistein, daidzein inhibited adipogenesis through stimulation of lipolysis, with for example, PKA-mediated hormone sensitive lipase. This is consistent with the increase in glycerol released from AD-MSCs. In conclusion, understanding that different sets of mechanisms of the two isoflavones on adipogenesis will help the design of novel strategies to prevent observed current epidemic levels of obesity, using isoflavones.

The anti-atherogenic aspect of metformin treatment in insulin resistant women with the polycystic ovary syndrome: role of the newly established pro-inflammatory adipokine Acute-phase Serum Amyloid A; evidence of an adipose tissue-monocyte axis

OBJECTIVE

Acute-phase Serum Amyloid A (ASAA) is a novel pro-inflammatory adipokine, increased in obese, insulin resistant subjects. Polycystic ovary syndrome (PCOS) is associated with inflammation and atherosclerosis. We assessed sera, adipose tissue (AT) mRNA and protein levels of ASAA of PCOS women and matched controls. Ex vivo regulation of AT ASAA by d-glucose, effects of metformin treatment on circulating ASAA in PCOS subjects and effects of sera from normal and PCOS subjects (before and after metformin) on ASAA production (THP-1 macrophages) were also studied.

METHODS AND RESULTS

Circulating ASAA (ELISA), subcutaneous and omental AT ASAA mRNA (RT-PCR) and protein (western blotting) were significantly higher in PCOS women (P<0.05). In AT explants, glucose significantly increased ASAA production and secretion (P<0.05, P<0.01). Furthermore, ASAA production (THP-1 macrophages) was significantly greater by sera from PCOS women compared to controls (P<0.01). ASAA protein production was significantly decreased by sera from PCOS women following 6 months of metformin treatment (P<0.05). After 6 months of metformin treatment, there was a significant decrease in circulating ASAA (P<0.05). Importantly, changes in intima media thickness were predictive of changes in circulating ASAA (P=0.034).

CONCLUSION

Serum and AT ASAA are increased in PCOS women and are elevated by glucose. Metformin treatment decreases serum ASAA in these women. An adipose tissue-monocyte axis may be pivotal in the pathogenesis of inflammation and atherosclerosis. ASAA may be a valuable diagnostic marker in the management of dysmetabolic states including PCOS.

Metabolic syndrome and polycystic ovary syndrome... and vice versa

The metabolic syndrome (MS) and the polycystic ovary syndrome (PCOS) appear to be interrelated, although they are distinct entities. Women with PCOS appear to be commonly affected by MS, while women with MS may display reproductive or endocrine features of PCOS. These clinical observations appear to be only partly attributable to the association of both syndromes with obesity and imply a reciprocal pathophysiologic relationship between PCOS and MS with potentially significant clinical sequelae. Adult women with MS are at a greater risk of developing cardiovascular disease; women with PCOS also appear to carry such an increased risk in their postmenopausal life. Conversely, women with MS may experience reproductive disturbances, reminiscent of PCOS, more commonly than their counterparts from the general population. This review presented the current epidemiology of MS in adults and adolescents with PCOS, as well as the limited amount of data on the prevalence of features of PCOS among women with MS or MS features. We also discuss the potential pathophysiologic mechanisms underlying the relationship between these interweaving, but distinct, syndromes.

Lipolysis and lipid mobilization in human adipose tissue

Triacylglycerol (TAG) stored in adipose tissue (AT) can be rapidly mobilized by the hydrolytic action of the three main lipases of the adipocyte. The non-esterified fatty acids (NEFA) released are used by other tissues during times of energy deprivation. Until recently hormone-sensitive lipase (HSL) was considered to be the key rate-limiting enzyme responsible for regulating TAG mobilization. A novel lipase named adipose triglyceride lipase/desnutrin (ATGL) has been identified as playing an important role in the control of fat cell lipolysis. Additionally perilipin and other proteins of the surface of the lipid droplets protecting or exposing the TAG core of the droplets to lipases are also potent regulators of lipolysis. Considerable progress has been made in understanding the mechanisms of activation of the various lipases. Lipolysis is under tight hormonal regulation. The best understood hormonal effects on AT lipolysis concern the opposing regulation by insulin and catecholamines. Heart-derived natriuretic peptides (i.e., stored in granules in the atrial and ventricle cardiomyocytes and exerting stimulating effects on diuresis and natriuresis) and numerous autocrine/paracrine factors originating from adipocytes and other cells of the stroma-vascular fraction may also participate in the regulation of lipolysis. Endocrine and autocrine/paracrine factors cooperate and lead to a fine regulation of lipolysis in adipocytes. Age, anatomical site, sex, genotype and species differences all play a part in the regulation of lipolysis. The manipulation of lipolysis has therapeutic potential in the metabolic disorders frequently associated with obesity and probably in several inborn errors of metabolism.

Ovarian and adipose tissue dysfunction in polycystic ovary syndrome: report of the 4th special scientific meeting of the Androgen Excess and PCOS Society

Significant advances have been made in our understanding of ovarian dysfunction in polycystic ovary syndrome (PCOS), and alterations in adipose tissue function are likely to play an important role in its pathophysiology. This review highlights the principal novel concepts presented at the 4th special scientific meeting of the Androgen Excess and PCOS Society, "Ovarian and Adipose Tissue Dysfunction: Potential Roles in Polycystic Ovary Syndrome," which occurred on June 6, 2008 in San Francisco, California.