Postnatal testosterone exposure results in insulin resistance, enlarged mesenteric adipocytes, and an atherogenic lipid profile in adult female rats: comparisons with estradiol and dihydrotestosterone

Preconceptional maternal hyperandrogenism and metabolic syndrome risk in male offspring: a long-term population-based study

PURPOSE

There is limited research on the effects of maternal hyperandrogenism (MHA) on cardiometabolic risk factors in male offspring. We aimed to compare the risk of metabolic syndrome (MetS) in sons of women with preconceptional hyperandrogenism (HA) to those of non-HA women in later life.

METHODS

Using data obtained from the Tehran Lipid and Glucose Cohort Study, with an average of 20 years follow-up, 1913 sons were divided into two groups based on their MHA status, sons with MHA (n = 523) and sons without MHA (controls n = 1390). The study groups were monitored from the baseline until either the incidence of events, censoring, or the end of the study period, depending on which occurred first. Age-scaled unadjusted and adjusted Cox regression models were utilized to evaluate the hazard ratios (HRs) and 95% confidence intervals (CIs) for the association between MHA and MetS in their sons.

RESULTS

There was no significant association between MHA and HR of MetS in sons with MHA compared to controls, even after adjustment (unadjusted HR (95% CI) 0.94 (0.80-1.11), P = 0.5) and (adjusted HR (95% CI) 0.98 (0.81-1.18), P = 0.8). Sons with MHA showed a HR of 1.35 for developing high fasting blood sugar compared to controls (unadjusted HR (95% CI) 1.35 (1.01-1.81), P = 0.04), however, after adjustment this association did not remain significant (adjusted HR (95% CI) 1.25 (0.90-1.74), P = 0.1).

CONCLUSION

The results suggest that preconceptional MHA doesn't increase the risk of developing MetS in sons in later life. According to this suggestion, preconceptional MHA may not have long-term metabolic consequences in male offspring.

Neonatal inhibition of androgen activity alters the programming of body weight and orexinergic peptides differentially in male and female rats

The involvement of androgens in the regulation of energy metabolism has been demonstrated. The main objective of the present research was to study the involvement of androgens in both the programming of energy metabolism and the regulatory peptides associated with feeding. For this purpose, androgen receptors and the main metabolic pathways of testosterone were inhibited during the first five days of postnatal life in male and female Wistar rats. Pups received a daily s.c. injection from the day of birth, postnatal day (P) 1, to P5 of Flutamide (a competitive inhibitor of androgen receptors), Letrozole (an aromatase inhibitor), Finasteride (a 5-alpha-reductase inhibitor) or vehicle. Body weight, food intake and fat pads were measured. Moreover, hypothalamic Agouti-related peptide (AgRP), neuropeptide Y (NPY), orexin, and proopiomelanocortin (POMC) were analyzed by quantitative real-time polymerase chain reaction assay. The inhibition of androgenic activity during the first five days of life produced a significant decrease in body weight in females at P90 but did not affect this parameter in males. Moreover, the inhibition of aromatase decreased hypothalamic AgRP mRNA levels in males while the inhibition of 5α-reductase decreased hypothalamic AgRP and orexin mRNA levels in female rats. Finally, food intake and visceral fat, but not subcutaneous fat, were affected in both males and females depending on which testosterone metabolic pathway was inhibited. Our results highlight the differential involvement of androgens in the programming of energy metabolism as well as the AgRP and orexin systems during development in male and female rats.

Sex differences in energy metabolism: natural selection, mechanisms and consequences

Metabolic homeostasis operates differently in men and women. This sex asymmetry is the result of evolutionary adaptations that enable women to resist loss of energy stores and protein mass while remaining fertile in times of energy deficit. During starvation or prolonged exercise, women rely on oxidation of lipids, which are a more efficient energy source than carbohydrates, to preserve glucose for neuronal and placental function and spare proteins necessary for organ function. Carbohydrate reliance in men could be an evolutionary adaptation related to defence and hunting, as glucose, unlike lipids, can be used as a fuel for anaerobic high-exertion muscle activity. The larger subcutaneous adipose tissue depots in healthy women than in healthy men provide a mechanism for lipid storage. As female mitochondria have higher functional capacity and greater resistance to oxidative damage than male mitochondria, uniparental inheritance of female mitochondria may reduce the transmission of metabolic disorders. However, in women, starvation resistance and propensity to obesity have evolved in tandem, and the current prevalence of obesity is greater in women than in men. The combination of genetic sex, programming by developmental testosterone in males, and pubertal sex hormones defines sex-specific biological systems in adults that produce phenotypic sex differences in energy homeostasis, metabolic disease and drug responses.

Sexual Dimorphism in Adipose-Hypothalamic Crosstalk and the Contribution of Aryl Hydrocarbon Receptor to Regulate Energy Homeostasis

There are fundamental sex differences in the regulation of energy homeostasis. Better understanding of the underlying mechanisms of energy balance that account for this asymmetry will assist in developing sex-specific therapies for sexually dimorphic diseases such as obesity. Multiple organs, including the hypothalamus and adipose tissue, play vital roles in the regulation of energy homeostasis, which are regulated differently in males and females. Various neuronal populations, particularly within the hypothalamus, such as arcuate nucleus (ARC), can sense nutrient content of the body by the help of peripheral hormones such leptin, derived from adipocytes, to regulate energy homeostasis. This review summarizes how adipose tissue crosstalk with homeostatic network control systems in the brain, which includes energy regulatory regions and the hypothalamic–pituitary axis, contribute to energy regulation in a sex-specific manner. Moreover, development of obesity is contingent upon diet and environmental factors. Substances from diet and environmental contaminants can exert insidious effects on energy metabolism, acting peripherally through the aryl hydrocarbon receptor (AhR). Developmental AhR activation can impart permanent alterations of neuronal development that can manifest a number of sex-specific physiological changes, which sometimes become evident only in adulthood. AhR is currently being investigated as a potential target for treating obesity. The consensus is that impaired function of the receptor protects from obesity in mice. AhR also modulates sex steroid receptors, and hence, one of the objectives of this review is to explain why investigating sex differences while examining this receptor is crucial. Overall, this review summarizes sex differences in the regulation of energy homeostasis imparted by the adipose–hypothalamic axis and examines how this axis can be affected by xenobiotics that signal through AhR.

The emergence of insulin resistance following a chronic high-fat diet regimen coincides with an increase in the reinforcing effects of nicotine in a sex-dependent manner

The present study assessed the sex-dependent effects of insulin resistance on the reinforcing effects of nicotine. Female and male rats received a chronic high-fat diet (HFD) or regular diet (RD) for 8 weeks. A subset of rats then received vehicle or a dose of streptozotocin (STZ; 25 mg/kg) that induces insulin resistance. To assess insulin resistance, glucose levels were measured 15, 30, 60, 120, and 180 min after an insulin injection (0.75 U/kg). Nine days later, the rats were given extended access to intravenous self-administration (IVSA) of nicotine (0.015, 0.03, 0.06 mg/kg) in an operant box where they consumed their respective diet ad libitum and performed responses for water deliveries. Each nicotine dose was delivered for 4 days with 3 intermittent days of abstinence in their home cage. The day after the last IVSA session, physical signs were compared following administration of mecamylamine (3.0 mg/kg) to precipitate nicotine withdrawal. The results revealed that there were no changes in insulin resistance or nicotine intake in HFD alone rats regardless of sex. Insulin resistance was observed in HFD-fed rats that received STZ, and the magnitude of this effect was greater in males versus females. Our major finding was that nicotine intake was greater among HFD + STZ female rats as compared to males. Lastly, the physical signs of withdrawal were similar across all groups. Our results suggest that females diagnosed with disorders that disrupt insulin signaling, such as diabetes may be at risk of greater vulnerability to nicotine use due to enhanced reinforcing effects of this drug.

Implicating androgen excess in propagating metabolic disease in polycystic ovary syndrome

Polycystic ovary syndrome (PCOS) has been traditionally perceived as a reproductive disorder due to its most common presentation with menstrual dysfunction and infertility. However, it is now clear that women with PCOS are at increased risk of metabolic dysfunction, from impaired glucose tolerance and type 2 diabetes mellitus to nonalcoholic fatty liver disease and cardiovascular disease. PCOS is characterised by androgen excess, with cross-sectional data showing that hyperandrogenism is directly complicit in the development of metabolic complications. Recent studies have also shown that C11-oxy _C19 androgens are emerging to be clinically and biochemically significant in PCOS, thus emphasising the importance of understanding the impact of both classic and C11-oxy _C19 androgens on women's health. Here we discuss androgen metabolism in the context of PCOS, and dissect the role played by androgens in the development of metabolic disease through their effects on metabolic target tissues in women.

The impact of androgen actions in neurons on metabolic health and disease

The male hormone testosterone exerts different effects on glucose and energy homeostasis in males and females. Testosterone deficiency predisposes males to visceral obesity, insulin resistance and type 2 diabetes. However, testosterone excess predisposes females to similar metabolic dysfunction. Here, we review the effects of testosterone actions in the central nervous system on metabolic function in males and females. In particular, we highlight changes within the hypothalamus that control glucose and energy homeostasis. We distinguish the organizational effects of testosterone in the programming of neural circuitry during development from the activational effects of testosterone during adulthood. Finally, we explore potential sites where androgen might be acting to impact metabolism within the central nervous system.

Developmental Programming of Ovarian Functions and Dysfunctions

The pathophysiological mechanisms underlying the origin of several ovarian pathologies remain unclear. In addition to the genetic basis, developmental insults are gaining attention as a basis for the origin of these pathologies. Such early insults include maternal over or under nutrition, stress, and exposure to environmental chemicals. This chapter reviews the development and physiological function of the ovary, the known ovarian pathologies, the developmental check points of ovarian differentiation impacted by developmental insults, the role played by steroidal and metabolic factors as mediaries, the epigenetic mechanisms via which these mediaries induce their effects, and the knowledge gaps for targeting future studies to ultimately aid in the development of improved treatments.

The Polycystic Ovary Syndrome and the Metabolic Syndrome: A Possible Chronobiotic-Cytoprotective Adjuvant Therapy

Polycystic ovary syndrome is a highly frequent reproductive-endocrine disorder affecting up to 8-10% of women worldwide at reproductive age. Although its etiology is not fully understood, evidence suggests that insulin resistance, with or without compensatory hyperinsulinemia, and hyperandrogenism are very common features of the polycystic ovary syndrome phenotype. Dysfunctional white adipose tissue has been identified as a major contributing factor for insulin resistance in polycystic ovary syndrome. Environmental (e.g., chronodisruption) and genetic/epigenetic factors may also play relevant roles in syndrome development. Overweight and/or obesity are very common in women with polycystic ovary syndrome, thus suggesting that some polycystic ovary syndrome and metabolic syndrome female phenotypes share common characteristics. Sleep disturbances have been reported to double in women with PCOS and obstructive sleep apnea is a common feature in polycystic ovary syndrome patients. Maturation of the luteinizing hormone-releasing hormone secretion pattern in girls in puberty is closely related to changes in the sleep-wake cycle and could have relevance in the pathogenesis of polycystic ovary syndrome. This review article focuses on two main issues in the polycystic ovary syndrome-metabolic syndrome phenotype development: (a) the impact of androgen excess on white adipose tissue function and (b) the possible efficacy of adjuvant melatonin therapy to improve the chronobiologic profile in polycystic ovary syndrome-metabolic syndrome individuals. Genetic variants in melatonin receptor have been linked to increased risk of developing polycystic ovary syndrome, to impairments in insulin secretion, and to increased fasting glucose levels. Melatonin therapy may protect against several metabolic syndrome comorbidities in polycystic ovary syndrome and could be applied from the initial phases of patients' treatment.

Impaired branched-chain amino acid metabolism may underlie the nonalcoholic fatty liver disease-like pathology of neonatal testosterone-treated female rats

Polycystic ovary syndrome (PCOS) is frequently associated with non-alcoholic fatty liver disease (NAFLD), but the mechanisms involved in the development of NAFLD in PCOS are not well known. We investigated histological changes and metabolomic profile in the liver of rat models of PCOS phenotype induced by testosterone or estradiol. Two-day old female rats received sc injections of 1.25 mg testosterone propionate (Testos; n = 10), 0.5 mg estradiol benzoate (E2; n = 10), or vehicle (control group, CNT; n = 10). Animals were euthanized at 90-94 d of age and the liver was harvested for histological and metabolomic analyses. Findings showed only Testos group exhibited fatty liver morphology and higher levels of ketogenic and branched-chain amino acids (BCAA). Enrichment analysis showed effects of testosterone on BCAA degradation pathway and mitochondrial enzymes related to BCAA metabolism. Testos group also had a decreased liver fatty acid elongase 2 (ELOVL2) activity. E2 group had reduced lipid and acylcarnitine metabolites in the liver. Both groups had increased organic cation transporters (SLC22A4 and SLC16A9) activity. These findings indicate that neonatal testosterone treatment, but not estradiol, produces histological changes in female rat liver that mimic NAFLD with testosterone-treated rats showing impaired BCAA metabolism and dysfunctions in ELOVL2, SLC22A4 and SLC16A9 activity.

Sex differences in the effects of androgens acting in the central nervous system on metabolism

One of the most sexually dimorphic aspects of metabolic regulation is the bidirectional modulation of glucose and energy homeostasis by testosterone in males and females. Testosterone deficiency predisposes men to metabolic dysfunction, with excess adiposity, insulin resistance, and type 2 diabetes, whereas androgen excess predisposes women to insulin resistance, adiposity, and type 2 diabetes. This review discusses how testosterone acts in the central nervous system, and especially the hypothalamus, to promote metabolic homeostasis or dysfunction in a sexually dimorphic manner. We compare the organizational actions of testosterone, which program the hypothalamic control of metabolic homeostasis during development, and the activational actions of testosterone, which affect metabolic function after puberty. We also discuss how the metabolic effect of testosterone is centrally mediated via the androgen receptor.

AKR1C3-Mediated Adipose Androgen Generation Drives Lipotoxicity in Women With Polycystic Ovary Syndrome

CONTEXT

Polycystic ovary syndrome (PCOS) is a prevalent metabolic disorder occurring in up to 10% of women of reproductive age. PCOS is associated with insulin resistance and cardiovascular risk. Androgen excess is a defining feature of PCOS and has been suggested as causally associated with insulin resistance; however, mechanistic evidence linking both is lacking. We hypothesized that adipose tissue is an important site linking androgen activation and metabolic dysfunction in PCOS.

METHODS

We performed a human deep metabolic in vivo phenotyping study examining the systemic and intra-adipose effects of acute and chronic androgen exposure in 10 PCOS women, in comparison with 10 body mass index-matched healthy controls, complemented by in vitro experiments.

RESULTS

PCOS women had increased intra-adipose concentrations of testosterone (P = 0.0006) and dihydrotestosterone (P = 0.01), with increased expression of the androgen-activating enzyme aldo-ketoreductase type 1 C3 (AKR1C3) (P = 0.04) in subcutaneous adipose tissue. Adipose glycerol levels in subcutaneous adipose tissue microdialysate supported in vivo suppression of lipolysis after acute androgen exposure in PCOS (P = 0.04). Mirroring this, nontargeted serum metabolomics revealed prolipogenic effects of androgens in PCOS women only. In vitro studies showed that insulin increased adipose AKR1C3 expression and activity, whereas androgen exposure increased adipocyte de novo lipid synthesis. Pharmacologic AKR1C3 inhibition in vitro decreased de novo lipogenesis.

CONCLUSIONS

These findings define an intra-adipose mechanism of androgen activation that contributes to adipose remodeling and a systemic lipotoxic metabolome, with intra-adipose androgens driving lipid accumulation and insulin resistance in PCOS. AKR1C3 represents a promising therapeutic target in PCOS.

Hypothalamic transcriptional expression of the kisspeptin system and sex steroid receptors differs among polycystic ovary syndrome rat models with different endocrine phenotypes

OBJECTIVES:

Polycystic ovary syndrome is a heterogeneous endocrine disorder that affects reproductive-age women. The mechanisms underlying the endocrine heterogeneity and neuroendocrinology of polycystic ovary syndrome are still unclear. In this study, we investigated the expression of the kisspeptin system and gonadotropin-releasing hormone pulse regulators in the hypothalamus as well as factors related to luteinizing hormone secretion in the pituitary of polycystic ovary syndrome rat models induced by testosterone or estradiol.

METHODS:

A single injection of testosterone propionate (1.25 mg) (n=10) or estradiol benzoate (0.5 mg) (n=10) was administered to female rats at 2 days of age to induce experimental polycystic ovary syndrome. Controls were injected with a vehicle (n=10). Animals were euthanized at 90-94 days of age, and the hypothalamus and pituitary gland were used for gene expression analysis.

RESULTS:

Rats exposed to testosterone exhibited increased transcriptional expression of the androgen receptor and estrogen receptor-β and reduced expression of kisspeptin in the hypothalamus. However, rats exposed to estradiol did not show any significant changes in hormone levels relative to controls but exhibited hypothalamic downregulation of kisspeptin, tachykinin 3 and estrogen receptor-α genes and upregulation of the gene that encodes the kisspeptin receptor.

CONCLUSIONS:

Testosterone- and estradiol-exposed rats with different endocrine phenotypes showed differential transcriptional expression of members of the kisspeptin system and sex steroid receptors in the hypothalamus. These differences might account for the different endocrine phenotypes found in testosterone- and estradiol-induced polycystic ovary syndrome rats.

A Guide for the Design of Pre-clinical Studies on Sex Differences in Metabolism

In animal models, the physiological systems involved in metabolic homeostasis exhibit a sex difference. Investigators often use male rodents because they show metabolic disease better than females. Thus, females are not used precisely because of an acknowledged sex difference that represents an opportunity to understand novel factors reducing metabolic disease more in one sex than the other. The National Institutes of Health (NIH) mandate to consider sex as a biological variable in preclinical research places new demands on investigators and peer reviewers who often lack expertise in model systems and experimental paradigms used in the study of sex differences. This Perspective discusses experimental design and interpretation in studies addressing the mechanisms of sex differences in metabolic homeostasis and disease, using animal models and cells. We also highlight current limitations in research tools and attitudes that threaten to delay progress in studies of sex differences in basic animal research.

Sex Differences in Androgen Regulation of Metabolism in Nonhuman Primates

The in-depth characterization of sex differences relevant to human physiology requires the judicious use of a variety of animal models and human clinical data. Nonhuman primates (NHPs) represent an important experimental system that bridges rodent studies and clinical investigations. NHP studies have been especially useful in understanding the role of sex hormones in development and metabolism and also allow the elucidation of the effects of pertinent dietary influences on physiology pertinent to disease states such as obesity and diabetes. This chapter summarizes the current state of our understanding of androgen effects on male and female NHP metabolism relevant to hypogonadism in human males and polycystic ovary syndrome in human females. This review will also focus on the interaction between altered androgen levels and dietary restriction and excess, in particular the Western-style diet that underlies significant human pathophysiology.

Hyperprolactinemia induced by hCG leads to metabolic disturbances in female mice

The metabolic syndrome is a growing epidemic; it increases the risk for diabetes, cardiovascular disease, fatty liver, and several cancers. Several reports have indicated a link between hormonal imbalances and insulin resistance or obesity. Transgenic (TG) female mice overexpressing the human chorionic gonadotropin β-subunit (hCGβ+ mice) exhibit constitutively elevated levels of hCG, increased production of testosterone, progesterone and prolactin, and obesity. The objective of this study was to investigate the influence of hCG hypersecretion on possible alterations in the glucose and lipid metabolism of adult TG females. We evaluated fasting serum insulin, glucose, and triglyceride levels in adult hCGβ+ females and conducted intraperitoneal glucose and insulin tolerance tests at different ages. TG female mice showed hyperinsulinemia, hypertriglyceridemia, and dyslipidemia, as well as glucose intolerance and insulin resistance at 6 months of age. A 1-week treatment with the dopamine agonist cabergoline applied on 5-week-old hCGβ+ mice, which corrected hyperprolactinemia, hyperandrogenism, and hyperprogesteronemia, effectively prevented the metabolic alterations. These data indicate a key role of the hyperprolactinemia-induced gonadal dysfunction in the metabolic disturbances of hCGβ+ female mice. The findings prompt further studies on the involvement of gonadotropins and prolactin on metabolic disorders and might pave the way for the development of new therapeutic strategies.

Prenatal Testosterone Exposure Leads to Gonadal Hormone-Dependent Hyperinsulinemia and Gonadal Hormone-Independent Glucose Intolerance in Adult Male Rat Offspring

Elevated testosterone levels during prenatal life lead to hyperandrogenism and insulin resistance in adult females. This study evaluated whether prenatal testosterone exposure leads to the development of insulin resistance in adult male rats in order to assess the influence of gonadal hormones on glucose homeostasis in these animals. Male offspring of pregnant rats treated with testosterone propionate or its vehicle (control) were examined. A subset of male offspring was orchiectomized at 7 wk of age and reared to adulthood. At 24 wk of age, fat weights, plasma testosterone, glucose homeostasis, pancreas morphology, and gastrocnemius insulin receptor (IR) beta levels were examined. The pups born to testosterone-treated mothers were smaller at birth and remained smaller through adult life, with levels of fat deposition relatively similar to those in controls. Testosterone exposure during prenatal life induced hyperinsulinemia paralleled by an increased HOMA-IR index in a fasting state and glucose intolerance and exaggerated insulin responses following a glucose tolerance test. Prenatal androgen-exposed males had more circulating testosterone during adult life. Gonadectomy prevented hyperandrogenism, reversed hyperinsulinemia, and attenuated glucose-induced insulin responses but did not alter glucose intolerance in these rats. Prenatal androgen-exposed males had decreased pancreatic islet numbers, size, and beta-cell area along with decreased expression of IR in gastrocnemius muscles. Gonadectomy restored pancreatic islet numbers, size, and beta-cell area but did not normalize IRbeta expression. This study shows that prenatal testosterone exposure leads to a defective pancreas and skeletal muscle function in male offspring. Hyperinsulinemia during adult life is gonad-dependent, but glucose intolerance appears to be independent of postnatal testosterone levels.

The Effects of a Single Developmentally Entrained Pulse of Testosterone in Female Neonatal Mice on Reproductive and Metabolic Functions in Adult Life

Early postnatal exposures to sex steroids have been well recognized to modulate predisposition to diseases of adulthood. There is a complex interplay between timing, duration and dose of endocrine exposures through environmental or dietary sources that may alter the sensitivity of target tissues to the exogenous stimuli. In this study, we determined the metabolic and reproductive programming effects of a single developmentally entrained pulse of testosterone (T) given to female mice in early postnatal period. CD-1 female mice pups were injected with either 5 μg of T enanthate (TE) or vehicle (control [CON] group) within 24 hours after birth and followed to adult age. A total of 66% of T-treated mice exhibited irregular cycling, anovulatory phenotype, and significantly higher ovarian weights than vehicle-treated mice. Longitudinal nuclear magnetic resonance measurements revealed that TE group had greater body weight, whole-body lean, and fat mass than the CON group. Adipose tissue cellularity analysis in TE group revealed a trend toward higher size and number than their littermate CONs. The brown adipose tissue of TE mice exhibited white fat infiltration with down-regulation of several markers, including uncoupling protein 1 (UCP-1), cell death-inducing DNA fragmentation factor, α-subunit-like effector A, bone morphogenetic protein 7 as well as brown adipose tissue differentiation-related transcription regulators. T-injected mice were also more insulin resistant than CON mice. These reproductive and metabolic reprogramming effects were not observed in animals exposed to TE at 3 and 6 weeks of age. Collectively, these data suggest that sustained reproductive and metabolic alterations may result in female mice from a transient exposure to T during a narrow postnatal developmental window.

Sex differences in metabolic homeostasis, diabetes, and obesity

There are fundamental aspects of the control of metabolic homeostasis that are regulated differently in males and females. This sex asymmetry represents an evolutionary paradigm for females to resist the loss of energy stores. This perspective discusses the most fundamental sex differences in metabolic homeostasis, diabetes, and obesity. Together, the role of genetic sex, the programming effect of testosterone in the prenatal period in males, and the activational role of sex hormones at puberty produce two different biological systems in males and females that need to be studied separately. These sex-specific differences in energy homeostasis and metabolic dysfunction represent an untested source of factors that can be harnessed to develop relevant sex-based therapeutic avenues for diabetes, metabolic syndrome, and obesity.

Perinatal androgen exposure and adipose tissue programming: is there an impact on body weight fate?

Obesity is a major concern in public health because it is one of the main risk factors for the development of non-transmissible chronic diseases. The fact that there is a clear sex dimorphism in normal body fat distribution points out the role of sex steroids as key factors in the regulation and function of the adipose cell. Androgens affect adipogenesis and fat metabolism in the adipose tissue of males and females. Hormonal disorders during pregnancy may affect the fetal tissues, with long-term implications leading to the development of pathologies during adult life. Obesity and metabolic disease are among these. In this regard, animal models have demonstrated an abnormal fat distribution and modifications in the size and function of adipose cells in the female and male offspring of mothers exposed to androgen excess during pregnancy.

Differences in neonatal exposure to estradiol or testosterone on ovarian function and hormonal levels

Exposure to an excess of androgen or estrogen can induce changes in reproductive function in adult animals that resemble polycystic ovary syndrome in humans. However, considerable differences exist among several types of animal models. Little is known about the molecular features of steroidogenesis and folliculogenesis in the ovaries of rats exposed to different sex steroids as neonates. Here, we evaluated the impact of androgen and estrogen exposure on the ovaries of adult female rats during their neonatal period in the gene expression of Lhr and Cyp17a1, two key players of steroidogenesis. We also assessed hormone levels, folliculogenesis and the theca-interstitial cell population. The study was performed on the second postnatal day in thirty female Wistar rats that were sorted into the following three intervention groups: testosterone, estradiol and vehicle (control group). The animals were euthanized 90 days after birth. The main outcomes were hormone serum levels, ovary histomorphometry and gene expression of Lhr and Cyp17a1 as analyzed via quantitative real-time PCR. We found that exposure to excess testosterone in early life increased the LH and testosterone serum levels, the LH/FSH ratio, ovarian theca-interstitial area and gene expression of Lhr and Cyp17a1 in adult rats. Estrogen induced an increase in the ovarian theca-interstitial area, the secondary follicle population and gene expression of Lhr and Cyp17a1. All animals exposed to the sex steroids presented with closed vaginas. Our data suggest that testosterone resulted in more pronounced reproductive changes than did estrogen exposure. Our results might provide some insight into the role of different hormones on reproductive development and on the heterogeneity of clinical manifestations of conditions such as polycystic ovary syndrome.

Central mechanisms of adiposity in adult female mice with androgen excess

OBJECTIVE

Androgen excess in women is associated with visceral adiposity. However, little is known on the mechanism through which androgen promotes visceral fat accumulation.

METHODS

To address this issue, female mice to chronic androgen excess using 5α-dihydrotestosterone (DHT) and studied the regulation of energy homeostasis was exposed.

RESULTS

DHT induced a leptin failure to decrease body weight associated with visceral adiposity but without alterations in leptin anorectic action. This paralleled leptin's failure to upregulate brown adipose tissue expression of uncoupling protein-1, associated with decreased energy expenditure (EE). DHT decreased hypothalamic proopiomelanocortin (pomc) mRNA expression and increased POMC intensity in neuronal bodies of the arcuate nucleus while simultaneously decreasing the intensity of POMC projections to the dorsomedial hypothalamus (DMH). This was associated with a failure of the melanocortin 4 receptor agonist melanotan-II to suppress body weight.

CONCLUSION

Taken together, these data indicate that androgen excess promotes visceral adiposity with reduced POMC neuronal innervation in the DMH, reduced EE but without hyperphagia.

Neonatal events, such as androgenization and postnatal overfeeding, modify the response to ghrelin

It is currently accepted that ambient, non-genetic factors influence perinatal development and evoke structural and functional changes that may persist throughout life. Overfeeding and androgenization after birth are two of these key factors that could result in “metabolic imprinting” of neuronal circuits early in life and, thereby, increase the body weight homeostatic “set point”, stimulate appetite, and result in obesity. Our aim was to determine the influence of these obesogenic factors on the response to ghrelin. We observed the expected orexigenic effect of ghrelin regardless of the nutritional or hormonal manipulations to which the animals were subjected to at early postnatal development and this effect remained intact at later stages of development. In fact, ghrelin responses increased significantly when the animals were subjected to one of the two manipulations, but not when both were combined. An increased response to ghrelin could explain the obese phenotype displayed by individuals with modified perinatal environment.

Developmental androgenization programs metabolic dysfunction in adult mice: Clinical implications

Emerging evidence supports a developmental origin for the metabolic syndrome in the context of polycystic ovary syndrome (PCOS) in which the fetal environment programs both reproductive and metabolic abnormalities that will occur in adulthood. To explore the role of developmental androgen excess in programming metabolic dysfunction in adulthood, we reported a mouse model system in which neonates were androgenized with testosterone. We compared female mice with neonatal exposure to testosterone (NTF) with control females (CF), control males (CM), and male mice with neonatal testosterone exposure (NTM). NTF develop many of the features of metabolic syndrome observed in women with PCOS. These features include increased food intake and lean mass, visceral adiposity with enlarged adipocytes, hypoadiponectinemia, decreased osteocalcin activity, insulin resistance, pre-diabetes, and hypertension. NTF also develop a novel form of leptin resistance independent of STAT3. In contrast, littermate NTM develop a phenotype of hypogonadotropic hypogonadism with decreased lean mass and food intake. These NTM mice exhibit subcutaneous adiposity without cardiometabolic alterations. We discuss the relevance of this mouse model of developmental androgenization to the metabolic syndrome and its clinical implications to human metabolic diseases.

Developmental androgen excess disrupts reproduction and energy homeostasis in adult male mice

Polycystic ovary syndrome is a common endocrine disorder in females of reproductive age and is believed to have a developmental origin in which gestational androgenization programs reproductive and metabolic abnormalities in offspring. During gestation, both male and female fetuses are exposed to potential androgen excess. In this study, we determined the consequences of developmental androgenization in male mice exposed to neonatal testosterone (NTM). Adult NTM displayed hypogonadotropic hypogonadism with decreased serum testosterone and gonadotropin concentrations. Hypothalamic KiSS1 neurons are believed to be critical to the onset of puberty and are the target of leptin. Adult NTM exhibited lower hypothalamic Kiss1 expression and a failure of leptin to upregulate Kiss1 expression. NTM displayed an early reduction in lean mass, decreased locomotor activity, and decreased energy expenditure. They displayed a delayed increase in subcutaneous white adipose tissue amounts. Thus, excessive neonatal androgenization disrupts reproduction and energy homeostasis and predisposes to hypogonadism and obesity in adult male mice.

Impact of neonatal manipulation of androgen receptor function on endocrine-metabolic programming in the juvenile female rat

The impact of neonatal androgen receptor (AR) stimulation/blockage, due to testosterone propionate (TP)/AR antagonist treatment, on individual anthropometry and neuroendocrine-metabolic function was evaluated in the juvenile female rat. Pups (age 5 days) were s.c. injected with TP (1.25 mg), flutamide (F; 1.75 mg), and TP + F or vehicle (control, CT) and studied on day 30 of age. Body weight (BW), parametrial adipose tissue (PMAT) mass, food intake, adipoinsular axis, and steroidogenic functions were examined. Opposite to TP-rats, F-treated rats developed hypophagia, grew slowly (BW and PMAT), and displayed heightened peripheral insulin sensitivity. These F effects were abrogated in TP + F animals. Accordingly, TP rats displayed hyperleptinemia, an effect fully prevented by F cotreatment. Finally, androgen-treated animals bore an irreversible ovarian dysfunction (reduced circulating levels of 17HOP4 and ovary 17HOP4 content and P450c17 mRNA abundance). These data indicate that early stimulation of AR enhanced energy store, blockage of AR activity resulted in some beneficial metabolic effects, and neonatally androgenized rats developed a severe ovarian dysfunction. Our study highlights the important role of AR in the early organizational programming of metabolic and neuroendocrine functions.

Animal models of the polycystic ovary syndrome phenotype

The etiology of the polycystic ovary syndrome (PCOS) remains unclear, despite its high prevalence among infertility disorders in women of reproductive age. Although there is evidence for a genetic component of the disorder, other causes, such as prenatal insults are considered among the potential factors that may contribute to the development of the syndrome. Over the past few decades, several animal models have been developed in an attempt to understand the potential contribution of exposure to excess steroids on the development of this syndrome. The current review summarizes the phenotypes of current animal models exposed to excess steroid during the prenatal and early postnatal period and how they compare with the phenotype seen in women with PCOS.

Rodent models of polycystic ovary syndrome

Rodents are clearly valuable models for assessing disruption of fertility. The effects of different steroid treatments at different stages of reproductive life through from fetal to adult have been assessed for effects on fertility, ovarian morphology, hypothalamic-pituitary function or metabolic consequences. The results show that steroid treatments do disrupt fertility in many cases, but the underlying mechanisms are complicated by the effects of the different treatments at multiple sites. As models for PCOS at the ovarian level however, there are a number of problems particularly related to the fact that rodents are multi-ovular species. Apart from an absence of ovulation and corpora lutea, many of the different steroid regimes result in an increase in large atretic, or cystic follicles that do not parallel PCOS in women. Indeed a number of treatments are given at times when they will cause disruption of the positive feedback effects of estradiol, thus blocking ovulation in adult life. The resulting ovarian morphology thus appears to be like that of PCOS but is in fact not a clear mimic. This review of the various studies highlights parallels and problems with the use of rodents to study the mechanisms underlying the development of PCOS in women.

Developmental androgen excess programs sympathetic tone and adipose tissue dysfunction and predisposes to a cardiometabolic syndrome in female mice

Among women, the polycystic ovarian syndrome (PCOS) is considered a form of metabolic syndrome with reproductive abnormalities. Women with PCOS show increased sympathetic tone, visceral adiposity with enlarged adipocytes, hypoadiponectinemia, insulin resistance, glucose intolerance, increased inactive osteocalcin, and hypertension. Excess fetal exposure to androgens has been hypothesized to play a role in the pathogenesis of PCOS. Previously, we showed that neonatal exposure to the androgen testosterone (NT) programs leptin resistance in adult female mice. Here, we studied the impact of NT on lean and adipose tissues, sympathetic tone in cardiometabolic tissues, and the development of metabolic dysfunction in mice. Neonatally androgenized adult female mice (NTF) displayed masculinization of lean tissues with increased cardiac and skeletal muscle as well as kidney masses. NTF mice showed increased and dysfunctional white adipose tissue with increased sympathetic tone in both visceral and subcutaneous fat as well as increased number of enlarged and insulin-resistant adipocytes that displayed altered expression of developmental genes and hypoadiponectinemia. NTF exhibited dysfunctional brown adipose tissue with increased mass and decreased energy expenditure. They also displayed decreased undercarboxylated and active osteocalcin and were predisposed to obesity during chronic androgen excess. NTF showed increased renal sympathetic tone associated with increased blood pressure, and they developed glucose intolerance and insulin resistance. Thus, developmental exposure to testosterone in female mice programs features of cardiometabolic dysfunction, as can be observed in women with PCOS, including increased sympathetic tone, visceral adiposity, insulin resistance, prediabetes, and hypertension.

Sex-stratified genome-wide association studies including 270,000 individuals show sexual dimorphism in genetic loci for anthropometric traits

Given the anthropometric differences between men and women and previous evidence of sex-difference in genetic effects, we conducted a genome-wide search for sexually dimorphic associations with height, weight, body mass index, waist circumference, hip circumference, and waist-to-hip-ratio (133,723 individuals) and took forward 348 SNPs into follow-up (additional 137,052 individuals) in a total of 94 studies. Seven loci displayed significant sex-difference (FDR<5%), including four previously established (near GRB14/COBLL1, LYPLAL1/SLC30A10, VEGFA, ADAMTS9) and three novel anthropometric trait loci (near MAP3K1, HSD17B4, PPARG), all of which were genome-wide significant in women (P<5×10(-8)), but not in men. Sex-differences were apparent only for waist phenotypes, not for height, weight, BMI, or hip circumference. Moreover, we found no evidence for genetic effects with opposite directions in men versus women. The PPARG locus is of specific interest due to its role in diabetes genetics and therapy. Our results demonstrate the value of sex-specific GWAS to unravel the sexually dimorphic genetic underpinning of complex traits.

Developmental programming: impact of prenatal testosterone excess on insulin sensitivity, adiposity, and free fatty acid profile in postpubertal female sheep

Prenatal T excess causes reproductive and metabolic disruptions including insulin resistance, attributes of women with polycystic ovary syndrome. This study tested whether increases in visceral adiposity, adipocyte size, and total free fatty acids underlie the insulin resistance seen in prenatal T-treated female sheep. At approximately 16 months of age, insulin resistance and adipose tissue partitioning were determined via hyperinsulinemic euglycemic clamp and computed tomography, respectively, in control and prenatal T-treated females. Three months later, adipocyte size and free fatty acid composition were determined. Results revealed that at the postpubertal time points tested, insulin sensitivity was increased, visceral adiposity and adipocyte size in both the sc and the visceral compartments were reduced, and circulating palmitic acid was increased in prenatal T-treated females relative to controls. In parallel studies, 20-month-old prenatal T-treated females tended to have increased basal insulin to glucose ratio. Relative to earlier findings of reduced insulin sensitivity of prenatal T-treated females during early life and adulthood, these findings of increased insulin sensitivity and reduced adiposity postpubertally are suggestive of a period of developmental adaptation. The disruption observed in free fatty acid metabolism a few months later correspond to a time point when the insulin sensitivity indices of prenatal T-treated animals appear to shift toward insulin resistance. In summary, current findings of improved insulin sensitivity and reduced visceral adiposity in postpubertal prenatal T-treated sheep relative to our earlier findings of reduced insulin sensitivity during early postnatal life and adulthood are indicative of a period of developmental adaptation.

Continuous administration of a P450 aromatase inhibitor induces polycystic ovary syndrome with a metabolic and endocrine phenotype in female rats at adult age

Studying the mechanisms for the complex pathogenesis of polycystic ovary syndrome (PCOS) requires animal models with endocrine, reproductive, and metabolic features of the syndrome. Hyperandrogenism seems to be a central factor in PCOS, leading to anovulation and insulin resistance. In female rats, continuous administration of letrozole, a nonsteroidal inhibitor of P450 aromatase, at 400 μg/d starting before puberty induces hyperandrogenemia and reproductive abnormalities similar to those in women with PCOS. However, despite high circulating testosterone levels, these rats do not develop metabolic abnormalities, perhaps because of their supraphysiological testosterone concentrations or because estrogen synthesis is completely blocked in insulin-sensitive tissues. To test the hypothesis that continuous administration of lower doses of letrozole starting before puberty would result in both metabolic and reproductive phenotypes of PCOS, we performed a 12-wk dose-response study. At 21 d of age, 46 female Wistar rats were divided into two letrozole groups (100 or 200 μg/d) and a control group (placebo). Both letrozole doses resulted in increased body weight, inguinal fat accumulation, anovulation, larger ovaries with follicular atresia and multiples cysts, endogenous hyperandrogemia, and lower estrogen levels. Moreover, rats that received 200 μg/d had insulin resistance and enlarged adipocytes in inguinal and mesenteric fat depots, increased circulating levels of LH, decreased levels of FSH, and increased ovarian expression of Cyp17a1 mRNA. Thus, continuous administration of letrozole, 200 μg/d, to female rats for 90 d starting before puberty results in a PCOS model with reproductive and metabolic features of the syndrome.

Sex differences in human adipose tissues - the biology of pear shape

Women have more body fat than men, but in contrast to the deleterious metabolic consequences of the central obesity typical of men, the pear-shaped body fat distribution of many women is associated with lower cardiometabolic risk. To understand the mechanisms regulating adiposity and adipose tissue distribution in men and women, significant research attention has focused on comparing adipocyte morphological and metabolic properties, as well as the capacity of preadipocytes derived from different depots for proliferation and differentiation. Available evidence points to possible intrinsic, cell autonomous differences in preadipocytes and adipocytes, as well as modulatory roles for sex steroids, the microenvironment within each adipose tissue, and developmental factors. Gluteal-femoral adipose tissues of women may simply provide a safe lipid reservoir for excess energy, or they may directly regulate systemic metabolism via release of metabolic products or adipokines. We provide a brief overview of the relationship of fat distribution to metabolic health in men and women, and then focus on mechanisms underlying sex differences in adipose tissue biology.

Effect of androgen treatment during foetal and/or neonatal life on ovarian function in prepubertal and adult rats

We investigated the effects of different windows of testosterone propionate (TP) treatment during foetal and neonatal life in female rats to determine whether and when excess androgen exposure would cause disruption of adult reproductive function. Animals were killed prepubertally at d25 and as adults at d90. Plasma samples were taken for hormone analysis and ovaries serial sectioned for morphometric analyses. In prepubertal animals, only foetal+postnatal and late postnatal TP resulted in increased body weights, and an increase in transitory, but reduced antral follicle numbers without affecting total follicle populations. Treatment with TP during both foetal+postnatal life resulted in the development of streak ovaries with activated follicles containing oocytes that only progressed to a small antral (smA) stage and inactive uteri. TP exposure during foetal or late postnatal life had no effect upon adult reproductive function or the total follicle population, although there was a reduction in the primordial follicle pool. In contrast, TP treatment during full postnatal life (d1-25) resulted in anovulation in adults (d90). These animals were heavier, had a greater ovarian stromal compartment, no differences in follicle thecal cell area, but reduced numbers of anti-Mullerian hormone-positive smA follicles when compared with controls. Significantly reduced uterine weights lead reduced follicle oestradiol production. These results support the concept that androgen programming of adult female reproductive function occurs only during specific time windows in foetal and neonatal life with implications for the development of polycystic ovary syndrome in women.

Prospective association of low total testosterone concentrations with an adverse lipid profile and increased incident dyslipidemia

BACKGROUND

Earlier studies have suggested that total testosterone concentrations influence the lipid metabolism. Whether these concentrations are prospectively associated with an adverse lipid profile and an increased risk of incident dyslipidemia has not yet been investigated.

METHODS AND RESULTS

Our study population consisted of 1468 men, aged 20–79 years, who were repeatedly examined as part of the population-based Study of Health in Pomerania. Serum total testosterone concentrations measured by the chemiluminescent enzyme immunoassays were categorized into age-specific quartiles. We used generalized estimating equations models to assess the prospective association between total testosterone concentrations and lipid profile components including total cholesterol (TC), low-density lipoprotein cholesterol, high-density lipoprotein cholesterol, and triglyceride (TG) concentrations, as well as incident dyslipidemia after 5 years of follow-up. Multivariate models revealed that total testosterone concentrations in the lowest quartile were associated with higher TC and TG concentrations in both cross-sectional [TC: 0.23 mmol/l (95% confidence interval, CI, 0.02–0.42); TG: 0.73 mmol/l (95% CI, 0.53–0.94)] and longitudinal analyses [TC: 0.20 mmol/l (95% CI, 0.03–0.27); TG: 0.62 mmol/l (95% CI, 0.43–0.80)], but not with high-density lipoprotein cholesterol or low-density lipoprotein cholesterol concentrations. Baseline prevalence of dyslipidemia was 57.1% with a crude incidence rate of 46.6 per 1000 person-years. Total testosterone concentrations in the lowest quartile predicted dyslipidemia; age-adjusted relative risks (RR) for men in quartiles 1, 2, and 3 as compared to quartile 4 (highest, reference) were 1.28 (95% CI, 1.06–1.54), 1.10 (95% CI, 0.91–1.33), and 1.05 (95% CI, 0.86–1.29), respectively. This effect was particularly strong among men aged 20–39 years (relative risk, 1.51; 95% CI, 1.08–2.10).

CONCLUSION

Low total testosterone concentrations are prospectively associated with an adverse lipid profile and increased risk of incident dyslipidemia. These findings are particularly interesting and may contribute to an explanation for the higher cardiovascular disease risk in men with lower total testosterone concentrations.

Developmental origin of reproductive and metabolic dysfunctions: androgenic versus estrogenic reprogramming

Polycystic ovary syndrome (PCOS) is one of the most common fertility disorders, affecting several million women worldwide. Women with PCOS manifest neuroendocrine, ovarian, and metabolic defects. A large number of animal models have evolved to understand the etiology of PCOS. These models provide support for the contributing role of excess steroids during development in programming the PCOS phenotype. However, considerable phenotypic variability is evident across animal models, depending on the quality of the steroid administered and the perinatal time of treatment relative to the developmental trajectory of the fetus/offspring. This review focuses on the reproductive and metabolic phenotypes of the various PCOS animal models that have evolved in the last decade to delineate the relative roles of androgens and estrogens in relation to the timing of exposure in programming the various dysfunctions that are part and parcel of the PCOS phenotype. Furthermore, the review addresses the contributory role of the postnatal metabolic environment in exaggerating the severity of the phenotype, the translational relevance of the various animal models to PCOS, and areas for future research.

Influence of having a male twin on body mass index and risk for dyslipidemia in middle-aged and old women

BACKGROUND

Animal experiments suggest that exposure to elevated levels of androgens during development by means of so-called hormonal programming causes metabolic aberrations at adulthood. An indirect strategy to address the possible importance of such an influence also in humans would be to study female dizygotic twins, presuming that those with a twin brother--due to diffusion of testosterone--have been exposed to higher androgen levels prenatally.

DESIGN

We have compared 8409 women with a male twin with 9166 women with a dizygotic female twin with respect to self-reported indices of anthropometry and metabolic aberrations at age 42 or older.

RESULTS

Body mass index (BMI), body weight and rate of dyslipidemia were moderately, but significantly, higher in women from opposite-sexed (OS) twin pairs; splitting for age revealed this difference to be present in those ≥ 60 years of age only.

CONCLUSION

The results (i) support the notion that comparisons of women with a twin brother with women from same-sexed twin pairs may be used to shed light on possible long-term effects of interindividual variations in early androgen exposure, and (ii) suggest that the effects of early androgen exposure on metabolism previously observed in animal experiments are of relevance also for humans.

Enhanced proinflammatory cytokine response to bacterial lipopolysaccharide in the adult male rat after either neonatal or prepubertal ablation of biological testosterone activity

A sex steroid-dependent modulation of the immune function in mammals is accepted, and evidence suggests that while estrogens enhance, androgens inhibit the immune response. The aim of this study was to explore in the adult male rat the effect of either neonatal flutamide (FTM) treatment or prepubertal orchidectomy (ODX) on endocrine markers in the basal condition and peripheral tumor necrosis factor alpha (TNFα) levels during inflammatory stress. For these purposes, (1) 5-day-old male rats were subcutaneously injected with either sterile vehicle alone or containing 1.75 mg FTM, and (2) 25-day-old male rats were sham operated or had ODX. Rats were sacrificed (at 100 days of age) in the basal condition for determination of peripheral metabolite levels. Additional rats were intravenously injected with bacterial lipopolysaccharide (LPS; 25 μg/kg body weight, i.v.) and bled for up to 4 h. Data indicate that (1) ODX increased peripheral glucocorticoid levels and reduced those of testosterone, whereas FTM-treated rats displayed low circulating leptin concentrations, and (2) LPS-induced TNFα secretion in plasma was significantly enhanced in the FTM and ODX groups. Our study supports that neonatal FTM treatment affected adiposity function, and adds data maintaining that androgens have a suppressive role in proinflammatory cytokine release in plasma during inflammation.

A single early postnatal estradiol injection affects morphology and gene expression of the ovary and parametrial adipose tissue in adult female rats

Events during early life can affect reproductive and metabolic functions in adulthood. We evaluated the programming effects of a single early postnatal estradiol injection (within 3h after birth) in female rats. We assessed ovarian and parametrial adipose tissue morphology, evaluated gene expression related to follicular development and adipose tissue metabolism, and developed a non-invasive volumetric estimation of parametrial adipose tissue by magnetic resonance imaging. Estradiol reduced ovarian weight, increased antral follicle size and number of atretic antral follicles, and decreased theca interna thickness in atretic antral follicles. Adult estradiol-injected rats also had malformed vaginal openings and lacked corpora lutea, confirming anovulation. Estradiol markedly reduced parametrial adipose tissue mass. Adipocyte size was unchanged, suggesting reduced adipocyte number. Parametrial adipose tissue lipoprotein lipase activity was increased. In ovaries, estradiol increased mRNA expression of adiponectin, complement component 3, estrogen receptor α, and glucose transporter 3 and 4; in parametrial adipose tissue, expression of complement component 3 was increased, expression of estrogen receptor α was decreased, and expression of leptin, lipoprotein lipase, and hormone-sensitive lipase was unaffected. These findings suggest that early postnatal estradiol exposure of female rats result in long-lasting effects on the ovary and parametrial adipose tissue at adult age.

Parametrial adipose tissue and metabolic dysfunctions induced by fructose-rich diet in normal and neonatal-androgenized adult female rats

Hyperandrogenemia predisposes an organism toward developing impaired insulin sensitivity. The aim of our study was to evaluate endocrine and metabolic effects during early allostasis induced by a fructose-rich diet (FRD) in normal (control; CT) and neonatal-androgenized (testosterone propionate; TP) female adult rats. CT and TP rats were fed either a normal diet (ND) or an FRD for 3 weeks immediately before the day of study, which was at age 100 days. Energy intake, body weight (BW), parametrial (PM) fat characteristics, and endocrine/metabolic biomarkers were then evaluated. Daily energy intake was similar in CT and TP rats regardless of the differences in diet. When compared with CT-ND rats, the TP-ND rats were heavier, had larger PM fat, and were characterized by basal hypoadiponectinemia and enhanced plasma levels of non-esterified fatty acid (NEFA), plasminogen activator inhibitor-1 (PAI-1), and leptin. FRD-fed CT rats, when compared with CT-ND rats, had high plasma levels of NEFA, triglyceride (TG), PAI-1, leptin, and adiponectin. The TP-FRD rats, when compared with TP-ND rats, displayed enhanced leptinemia and triglyceridemia, and were hyperinsulinemic, with glucose intolerance. The PM fat taken from TP rats displayed increase in the size of adipocytes, decrease in adiponectin (protein/gene), and a greater abundance of the leptin gene. PM adipocyte response to insulin was impaired in CT-FRD, TP-ND, and TP-FRD rats. A very short duration of isocaloric FRD intake in TP rats induced severe metabolic dysfunction at the reproductive age. Our study supports the hypothesis that the early-androgenized female rat phenotype is highly susceptible to developing endocrine/metabolic dysfunction. In turn, these abnormalities enhance the risk of metabolic syndrome, obesity, type 2 diabetes, and cardiovascular disease.

Developmental programming: impact of prenatal testosterone excess and postnatal weight gain on insulin sensitivity index and transfer of traits to offspring of overweight females

Polycystic ovary syndrome (PCOS) is the most common endocrinopathy of reproductive-aged women and is exacerbated by obesity. Exposure of ewes to excess testosterone (T) from d 30-90 of gestation culminates in anovulation, functional hyperandrogenism, LH excess, and polyfollicular ovaries, features similar to those of women with PCOS, with some reproductive defects programmed by androgenic actions of T and others not. Excess weight gain during postnatal life increases the severity of these reproductive defects. Prenatal T-treated ewes also manifest reduced insulin sensitivity, a feature found in more than 70% of PCOS women. We tested the hypotheses that reduced insulin sensitivity of prenatal T-treated ewes is programmed by androgenic actions of T, and excess postnatal weight gain exaggerates this defect. In addition, we tested whether disruptive effects of excess weight gain on insulin sensitivity index are transferred to female offspring. Insulin sensitivity was assessed using iv glucose tolerance tests. Results revealed that disruptive effects of prenatal T excess on insulin sensitivity were programmed by androgenic action of T and postnatal overfeeding-impaired insulin sensitivity in both T-treated and controls and that prenatal T-treated sheep tend to manifest such overfeeding impairments earlier than controls. Importantly, offspring of overweight controls also manifest defects in insulin dynamics supportive of intergenerational transfer of obesity-related traits. The findings are of relevance in the context of developmental programming of insulin resistance by prenatal steroids and excess weight gain.

Targeting insulin sensitivity in the treatment of polycystic ovary syndrome

Targeting insulin resistance may result in a list of benefits for women with PCOS, including hormonal, metabolic and ovulatory (and fertility) improvements. The therapeutic strategy to treat PCOS should however depend on the clinical situation, the phenotype, the degree of androgen excess, age, the presence of infertility and the woman's desire to conceive, the presence of obesity and, finally, the spectrum of metabolic abnormalities and the need to treat or prevent long-term associated comorbidities. According to the needs, therapeutic options include, alone or in combination, lifestyle management, particularly in the presence of obesity, the use of insulin sensitizers, metformin and thiazolidinediones, antiandrogens or estro-progestins.

The association of endogenous sex hormones, adiposity, and insulin resistance with incident diabetes in postmenopausal women

CONTEXT

In postmenopausal women, endogenous bioavailable testosterone (T) and estradiol (E2) have been positively associated, and SHBG has been negatively associated, with incident type 2 diabetes (T2DM). Previous studies have not explored possible factors explaining these relationships.

OBJECTIVE

Our objective was to examine the association of endogenous sex hormones with incident T2DM in postmenopausal women and possible explanatory factors.

DESIGN, SETTING, AND PARTICIPANTS

The Multi-Ethnic Study of Atherosclerosis (MESA) is a prospective study that included 1612 postmenopausal women aged 45-84 yr, followed between the years 2000-2006, who were not taking hormone replacement therapy, had no prevalent cardiovascular disease or diabetes, and had complete ascertainment of sex hormones.

MAIN OUTCOME MEASURES

T2DM was defined based on fasting glucose and/or treatment for diabetes.

RESULTS

There were 116 incident cases of diabetes during follow-up. Across higher quartiles of bioavailable T and E2 and lower quartiles of SHBG, we found significantly greater hazards of developing incident T2DM (all P for trend <or=0.001). After adjustment for body mass index and insulin resistance estimated by homeostasis model assessment of insulin resistance, bioavailable T was no longer associated with incident T2DM. The associations of E2 and SHBG with incident T2DM were partially explained by body mass index and insulin resistance but persisted in fully adjusted models (both P for trend <0.02). Dehydroepiandrosterone had no relationship with incident T2DM.

CONCLUSIONS

Adiposity and insulin resistance explained most of the association of bioavailable T but only partially explained the associations of E2 and SHBG with incident T2DM among postmenopausal women.