Androgen receptor: a new player associated with apoptosis and proliferation of pancreatic beta-cell in type 1 diabetes mellitus

The Influences of Perinatal Androgenic Exposure on Cardiovascular and Metabolic Disease of Offspring of PCOS

Hyperandrogenism is an endocrine disorder affecting a large population of reproductive-aged women, thus proportionally high number of fetuses are subjected to prenatal androgenic exposure (PNA). The short-term stimulations at critical ontogenetic stages can wield lasting influences on the health. The most commonly diagnosed conditions in reproductive age women is polycystic ovary syndrome (PCOS). PNA may affect the growth and development of many systems in the whole body and disrupts the normal metabolic trajectory in the offspring of PCOS, contributing to the prevalence of cardiovascular and metabolic diseases (CVMD), including myocardial hypertrophy, hypertension, hyperinsulinemia, insulin resistance, hyperglycemia, obesity, and dyslipidemia, which are the leading causes of hospitalizations in young PCOS offspring. In this review, we focus on the effects of prenatal androgenic exposure on the cardiovascular and metabolic diseases in offspring, discuss the possible pathogenesis respectively, and summarize potential management strategies to improve metabolic health of PCOS offspring. It is expected that the incidence of CVMD and the medical burden will be reduced in the future.

New Insight into Molecular and Hormonal Connection in Andrology

Hormones and cytokines are known to regulate cellular functions in the testes. These biomolecules induce a broad spectrum of effects on various level of spermatogenesis, and among them is the modulation of cell junction restructuring between Sertoli cells and germ cells in the seminiferous epithelium. Cytokines and androgens are closely related, and both correct testicular development and the maintenance of spermatogenesis depend on their function. Cytokines also play a crucial role in the immune testicular system, activating and directing leucocytes across the endothelial barrier to the inflammatory site, as well as in increasing their adhesion to the vascular wall. The purpose of this review is to revise the most recent findings on molecular mechanisms that play a key role in male sexual function, focusing on three specific molecular patterns, namely, cytokines, miRNAs, and endothelial progenitor cells. Numerous reports on the interactions between the immune and endocrine systems can be found in the literature. However, there is not yet a multi-approach review of the literature underlying the role between molecular patterns and testicular and sexual function.

The risk factors of gestational diabetes mellitus in patients with polycystic ovary syndrome: What should we care

ABSTRACT

The influencing factors of gestational diabetes mellitus (GDM) in the polycystic ovary syndrome (PCOS) patients remain unclear, we aimed to investigate the risk factors of GDM in patients with PCOS, to provide reliable evidence for the prevention and treatment of GDM in PCOS patients.PCOS patients treated in our hospital from January 1, 2019 to October 31, 2020 were included. The personal and clinical treatment details of GDM and no GDM patients were analyzed. Logistic regressions were performed to analyze the factors influencing the occurrence of GDM.A total of 196 PCOS patients were included, the incidence of GDM in patients with PCOS was 23.98%. There were significant differences in the age, body mass index, insulin resistance index, fasting insulin, testosterone, androstenedione, and sex hormone-binding protein between GDM and no GDM patients with PCOS (all P < .05), and no significant differences in the family history of GDM, the history of adverse pregnancy, and multiple pregnancies were found (all P > .05). Age ≥30 years (odds ratio (OR) 2.418, 95% confidence interval (CI) 1.181-3.784), body mass index ≥24 kg/m2 (OR 1.973, 95%CI 1.266-3.121), insulin resistance index ≥22.69 (OR 2.491, 95%CI 1.193-4.043), fasting insulin ≥22.71 mIU/L (OR 2.508, 95%CI 1.166-5.057), testosterone ≥2.85 nmol/L (OR 1.821, 95%CI 1.104-2.762), androstenedione ≥6.63 nmol/L (OR 1.954, 95%CI 1.262-2.844), sex hormone-binding protein <64.22 nmol/L (OR 1.497, 95%CI 1.028-2.016) were the independent risk factors of GDM in patients with PCOS (all P < .05). The incidence of preeclampsia, premature delivery, premature rupture of membranes, polyhydramnios, and postpartum hemorrhage in the GDM group was significantly higher than that of the no-GDM group (all P < .05). There was no significant difference in the incidence of oligohydramnios between the 2 groups (P = .057).The incidence of GDM in PCOS patients is high, and the measures targeted at the risk factors are needed to reduce the occurrence of GDM in patients with PCOS.

In utero exposure to phenanthrene induced islet cell dysfunction in adult mice: Sex differences in the effects and potential causes

Epidemiological studies show that the burden of polycyclic aromatic hydrocarbons in human body is associated with the occurrence of insulin resistance and diabetes. In the present study, pregnant mice were exposed to phenanthrene (Phe) at doses of 0, 60 and 600 μg/kg body weight of by gavage once every 3 days. The female F1 mice at 120 days of age showed no change in their fasting glucose levels (FGLs) but exhibited significantly decreased homeostasis model assessment (HOMA) β-cell (49% and 43%) and significantly downregulated pancreatic proinsulin gene (ins2) transcription. The downregulation of transcription factors, such as PDX1, PAX4 and FGF21, indicated impaired development and function of β-cells. The significantly reduced α-cell mass in 60 and 600 μg/kg groups, and the significantly downregulated expression of proglucagon gene gcg and ARX in the 600 μg/kg group suggested that the development and function of α-cells had been impacted. The males exhibited significantly increased FGLs (1.14- and 1.15-fold) in Phe exposed treatments and significantly elevated HOMA β-cell (3.15-fold) in the 600 μg/kg group. Upregulated ins2 transcription and FGF21 protein in male mice prenatally exposed to 600 μg/kg Phe suggested that these animals appeared compensatory enhancement in β-cell function. The reduced serum estradiol levels and downregulated pancreatic estrogen receptor α and β were responsible for the dysfunction of β-cells in the females. In the males, the significantly elevated androgen levels in the 600 μg/kg group might be related to the upregulated ins2 transcription, and the increased expression of pancreatic FGF21 further demonstrated the enhancement of β-cell potential. The results will be helpful for assessing the risk of developing diabetes in adulthood after prenatal exposure to phenanthrene.

Insulin and glucose responses to hypoxia in male and female neonatal rats: Effects of the androgen receptor antagonist flutamide

Hypoxia is common with preterm birth and may lead to long-term effects on adult pancreatic endocrine function and insulin sensitivity. This phenomenon may be sexually dimorphic due to the hypoxia-induced augmentation of the neonatal androgen surge in male newborns. We evaluated this phenomenon by pretreating neonatal rats on postnatal days (PD) 1, 6, 13, or 20 with flutamide (a nonsteroidal androgen receptor antagonist) at a standard or a high dose (10 or 50 mg/kg) compared to vehicle control. One day later, neonatal rats were exposed to either acute normoxic or hypoxic separation (fasting) for 90 min, and blood was sampled for the measurement of insulin and glucose and the calculation of HOMA-IR as an index of insulin resistance. During normoxic and hypoxic separation (fasting), flutamide increased insulin secretion in PD2, PD7, and PD14 pups, high dose flutamide attenuated insulin secretion, and high dose flutamide attenuated the increase in HOMA-IR due to hypoxia. Our studies suggest a unique role of the androgen receptor in the control of neonatal pancreatic function, possibly by blocking a direct effect of neonatal testosterone or in response to indirect regulatory effects of androgens on insulin sensitivity.

Exposure to Aroclor 1254 differentially affects the survival of pancreatic β-cells and α-cells in the male mice and the potential reason

Previous works showed that chronic exposure to Aroclor 1254 disrupted glucose homeostasis and induced insulin resistance in male mice. To further observe the different effects of Aroclor 1254 exposure on the pancreatic α-cells and β-cells, male mice were exposed to Aroclor 1254 (0, 0.5, 5, 50, 500 μg/kg) for 60 days, the pancreas was performed a histological examination. The results showed that the percentage of apoptosis cell (indicated by TUNEL assay) was increased in both α-cells and β-cells, as the Aroclor 1254 dose was increased; the proliferation (indicated by PCNA expression) rate of β-cells was elevated while that of α-cells was not affected, resulting in an increased β-cell mass and a decreased α-cell mass in a dose-depend manner. The number of Pdx-1 positive β-cells was significantly increased whereas that of Arx positive α-cells was markedly decreased, indicating an enhanced β-cell neogenesis and a weakened α-cell neogenesis. The drastically reduction of serum testosterone levels in all the treatments suggested an anti-androgenic potency of Aroclor 1254. The up-regulation of estrogen receptors (ERα and ERβ) and androgen receptor in β-cells might be responsible for the increased β-cell mass and neogenesis.

Comparison of the clinicopathological features of pancreatic solid pseudopapillary neoplasms between males and females: gender does matter

BACKGROUND

Solid pseudopapillary neoplasms (SPN) of the pancreas are a rare and low-grade malignant entity with a female predominance. However, it also occurs in males, but the rarity and lack of concern makes its clinicopathological features unclarified.

METHODS

The morphological, immunohistochemical, prognostic features and CTNNB1 exon 3 mutation status of SPN were compared semi-quantitively between 9 male and 21 female patients.

RESULTS

SPN in males grew in a distinctive solid pattern, with abundant fibrotic stroma and clear cells. Collagen tended to be the main component of tumor stroma in males, while hyaluronan composed a considerable proportion in females. A much stronger expression of androgen receptor (AR) was found in males, and CD56 and/or synaptophysin (Syn) was expressed frequently in both genders. All patients survived. One male patient had post-operational liver nodules and accepted interventional therapy without biopsy. Mutations of CTNNB1 exon 3 were observed in all cases, distributed at codon 32, 33 and 37 in both genders, as well as 34, 41 and 62 in females.

CONCLUSION

SPN in males presented with significantly different morphological features from that in females, which might be helpful in differential diagnosis, especially when with extensive positivity for CD56 and/or Syn. The stronger expression of AR in males might be a clue to explore the underlying mechanism of the gender difference.

Elevated androgen levels induce hyperinsulinemia through increase in Ins1 transcription in pancreatic beta cells in female rats

Hyperandrogenism is associated with hyperinsulinemia and insulin resistance in adult females. We tested whether androgens dysregulate pancreatic beta cell function to induce hyperinsulinemia through transcriptional regulation of insulin gene (Ins) in the islets. Adult female Wistar rats implanted with dihydrotestosterone (DHT; 7.5-mg, 90-d release) or placebo pellets were examined after 10 weeks. DHT exposure increased plasma DHT levels by 2-fold similar to that in polycystic ovary syndrome in women. DHT exposure induced hyperinsulinemia with increased HOMA-IR index in fasting state and glucose intolerance and exaggerated insulin responses following glucose tolerance test. DHT females had no change in islet number, size and beta cell proliferation/apoptosis but exhibited significant mitochondrial dysfunction (higher ADP/ATP ratio, decreased mtDNA copy number, increased reactive oxygen production and downregulation of mitochondrial biogenesis) and enhanced glucose-stimulated insulin secretion. Ins expression was increased in DHT islets. In vitro incubation of control islets with DHT dose dependently stimulated Ins transcription. Analysis of Ins1 gene revealed a putative androgen responsive element in the promoter. Chromatin-immunoprecipitation assays showed that androgen receptors bind to this element in response to DHT stimulation. Furthermore, reporter assays showed that the promoter element is highly responsive to androgens. Insulin-stimulated glucose uptake in skeletal muscle was decreased with associated decrease in IRβ expression in DHT females. Our studies identified a novel androgen-mediated mechanism for the control of Ins expression via transcriptional regulation providing a molecular mechanism linking elevated androgens and hyperinsulemia. Decreased IRβ expression in the skeletal muscles may contribute, in part, to glucose intolerance in this model.

MicroRNA-205 is associated with diabetes mellitus-induced erectile dysfunction via down-regulating the androgen receptor

As a major class of regulatory genes in majority metazoans, microRNAs (miRs) play an important role in various diseases including diabetes mellitus (DM). Lack of androgens has previously been associated with DM-induced erectile dysfunction (DMED). In addition, the biological functioning of androgen is mediated by androgen receptor (AR). Herein, we sought to investigate whether miRs participate in AR-associated DMED. Sprague-Dawlay rats were employed to establish DMED models. After modelling, levels of miR-205 and AR in their cavernous bodies were measured. The relationship between miR-205 and AR was verified using a dual-luciferase reporter gene assay. The underlying regulatory mechanisms of miR-205 were investigated in concert with the treatment of mimics or inhibitors of miR-205, or AR overexpression in the cavernous smooth muscle cells (CSMCs) isolated from rats with DMED. Meanwhile, the effects of miR-205 and AR on cell proliferation and apoptosis were evaluated using MTT assay and flow cytometry respectively. Rats with DMED presented with increased miR-205 and decreased AR levels in the cavernous bodies. AR was identified as a target gene of miR-205. Down-regulation of miR-205 or up-regulation of AR could increase proliferation and inhibits apoptosis of CSMCs in addition to improvements in the erectile functioning of rats with DMED. In summary, miR-205 may contribute to the pathogenesis of DMED via down-regulation of AR expressions.

Raffia palm (Raphia hookeri) wine inhibits glucose diffusion; improves antioxidative activities; and modulates dysregulated pathways and metabolites in oxidative pancreatic injury

Raffia palm wine is a natural drink from the stem of Raffia palm (Raphia hookeri) tree with nutritional and medicinal properties. The effect of fermentation was investigated on its antidiabetic and antioxidative effects in yeast cells and pancreatic tissues, respectively. Both unfermented and fermented palm wine significantly increased glucose uptake, reduced glutathione level (GSH), superoxide dismutase, and catalase activities. They also inhibited glucose diffusion, myeloperoxidase, and ATPase activities as well as decreased malondialdehyde and nitric oxide levels. They also led to the inactivation of oxidative metabolic pathways in oxidative pancreas with the generation of adenosine, sugar and inositol metabolites, selenium (enzyme co-factor) and vitamin metabolites owing to concomitant activation of vitamins, lipid, steroids, inositol, and sulfate/sulfite metabolic pathways. The results suggest the antidiabetic and antioxidative potentials of unfermented and fermented palm wine and may be attributed to the LC-MS-identified compounds which were mainly polyphenols and its glycosides, vitamins, and amino acids. PRACTICAL APPLICATIONS: Raffia palm wine is among the natural beverages employed for social, nutritional, and medicinal purposes. However, there are limited studies on its medicinal properties. This study reports for the first time, the ability of Raffia palm wine to stimulate glucose uptake, inhibit glucose diffusion, and ameliorate pancreatic oxidative injury, as well as the possible associated metabolic pathways that may be involved. These findings will further contribute in understanding the antidiabetic effect of Raffia palm wine, and the possible metabolic pathways involved.

Role of androgens in energy metabolism affecting on body composition, metabolic syndrome, type 2 diabetes, cardiovascular disease, and longevity: lessons from a meta-analysis and rodent studies

Testosterone is a sex hormone produced by testicular Leydig cells in males. Blood testosterone concentrations increase at three time-periods in male life-fetal, neonatal (which can be separated into newborn and infant periods), and pubertal stages. After peaking in the early 20s, the blood bioactive testosterone level declines by 1-2% each year. It is increasingly apparent that a low testosterone level impairs general physical and mental health in men. Here, this review summarizes recent systematic reviews and meta-analyses of epidemiological studies in males (including cross-sectional, longitudinal, and androgen deprivation studies, and randomized controlled testosterone replacement trials) in relation to testosterone and obesity,  body composition, metabolic syndrome, type 2 diabetes, cardiovascular disease, and longevity. Furthermore, underlying mechanisms are discussed using data from rodent studies involving castration or androgen receptor knockout. This review provides an update understanding of the role of testosterone in energy metabolism. Abbreviations AR: androgen receptor; CV: cardiovascular; FDA: US Food and Drug Administration; HFD: high-fat diet; KO: knockout; MetS: metabolic syndrome; RCT: randomized controlled trial; SHBG: sex hormone binding globulin; SRMA: systematic review and meta-analysis; TRT: testosterone replacement therapy; T2DM:type 2 diabetes mellitus.

Androgen signaling expands β-cell mass in male rats and β-cell androgen receptor is degraded under high-glucose conditions

A deficient pancreatic β-cell mass increases the risk of type 2 diabetes mellitus. Here, we investigated the effects of testosterone on the development of pancreatic β-cell mass in male rats. The β-cell mass of male rats castrated at 6 wk of age was reduced to ~30% of that of control rats at 16 wk of age, and castration caused glucose intolerance. Loss of β-cell mass occurred because of decreases in islet density per pancreas and β-cell cluster size. Castration was negatively associated with the number of Ki-67-positive β-cells and positively associated with the number of TUNEL-positive β-cells. These β-cell changes could be prevented by testosterone treatment. In contrast, castration did not affect β-cell mass in male mice. Androgen receptor (AR) localized differently in mouse and rat β-cells. Testosterone enhanced the viability of INS-1 and INS-1 #6, which expresses high levels of AR, in rat β-cell lines. siRNA-mediated AR knockdown or AR antagonism with hydroxyflutamide attenuated this enhancement. Moreover, testosterone did not stimulate INS-1 β-cell viability under high d-glucose conditions. In INS-1 β-cells, d-glucose dose dependently (5.5-22.2 mM) downregulated AR protein levels both in the presence and absence of testosterone. The intracellular calcium chelator (BAPTA-AM) could prevent this decrease in AR expression. AR levels were also reduced by a calcium ionophore (A23187), but not by insulin, in the absence of the proteasome inhibitor MG132. Our results indicate that testosterone regulates β-cell mass, at least in part, by AR activation in the β-cells of male rats and that the β-cell AR is degraded under hyperglycemic conditions.

Clinical and laboratory indicators of polycystic ovary syndrome in Chinese Han nationality with different Rotterdam criteria-based phenotypes

The aim of this study was to investigate the clinical, endocrinic and metabolic indicators in polycystic ovary syndrome (PCOS) with different Rotterdam criteria (RC)-based subtypes, thus to guide the treatments. Six hundred and forty-seven PCOS cases were divided into four groups, with 60 cases set as the control group, the clinical and endocrinic indicators of different subtypes were evaluated. Group A was the most common and the most serious (63.2%), while group B was the least (9%). The clinical signs, as well as the endocrinic and metabolic characteristics, of the two groups were similar, but group A exhibited higher androgen level and hirsutism score. The phenotypes of group C (15.6%) and group D (12.9%) were mild, but compared with the control group, luteinizing hormone (LH) and LH/follicle stimulating hormone (FSH) were significantly increased. Insulin resistance in these four subtypes were positively correlated with apolipoprotein B (ApoB)/apolipoprotein A1 (ApoA1), while only positively correlated with serum total testosterone, and negatively correlated with LH/FSH in group A. RC-PCOS typing could reflect the basic characteristics of the disease. Hyperandrogenism was the main basis for distinguishing PCOS, although the non-hyperandrogenism group could represent a relatively mild phenotype of PCOS, there might exist different pathogenic pathways.

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.

Abnormal infant islet morphology precedes insulin resistance in PCOS-like monkeys

Polycystic ovary syndrome (PCOS) is prevalent in reproductive-aged women and confounded by metabolic morbidities, including insulin resistance and type 2 diabetes. Although the etiology of PCOS is undefined, contribution of prenatal androgen (PA) exposure has been proposed in a rhesus monkey model as premenopausal PA female adults have PCOS-like phenotypes in addition to insulin resistance and decreased glucose tolerance. PA female infants exhibit relative hyperinsulinemia, suggesting prenatal sequelae of androgen excess on glucose metabolism and an antecedent to future metabolic disease. We assessed consequences of PA exposure on pancreatic islet morphology to identify evidence of programming on islet development. Islet counts and size were quantified and correlated with data from intravenous glucose tolerance tests (ivGTT) obtained from dams and their offspring. Average islet size was decreased in PA female infants along with corresponding increases in islet number, while islet fractional area was preserved. Infants also demonstrated an increase in both the proliferation marker Ki67 within islets and the beta to alpha cell ratio suggestive of enhanced beta cell expansion. PA adult females have reduced proportion of small islets without changes in proliferative or apoptotic markers, or in beta to alpha cell ratios. Together, these data suggest in utero androgen excess combined with mild maternal glucose intolerance alter infant and adult islet morphology, implicating deviant islet development. Marked infant, but subtle adult, morphological differences provide evidence of islet post-natal plasticity in adapting to changing physiologic demands: from insulin sensitivity and relative hypersecretion to insulin resistance and diminished insulin response to glucose in the mature PCOS-like phenotype.

Chronic exposure to tributyltin chloride induces pancreatic islet cell apoptosis and disrupts glucose homeostasis in male mice

It has been reported that organotin compounds such as triphenyltin or tributyltin (TBT) induce diabetes and insulin resistance. However, histopathological effects of organotin compounds on the Islets of Langerhans and exocrine pancreas are still unclear. In the present study, male KM mice were orally administered with TBT (0.5, 5, and 50 μg/kg) once every 3 days. The fasting plasma glucose levels significantly elevated, and the levels of serum insulin or glucagon decreased in the animals treated with TBT for 60 days. In animals treated for 45 days, the number of apoptotic cells in the islets and exocrine pancreas was elevated in a dose-dependent manner. The percentage of proliferating (PCNA-positive) cells was decreased in the islets, while it was increased in exocrine acinar cells. Immunohistochemistry analysis showed that estrogen receptor (ER) and androgen receptor (AR) were present in vascular endothelium, ductal cells, and islet cells, but absent from pancreatic exocrine cells. TBT exposure decreased the production of estradiol and triiodothyronine and elevated the concentration of testosterone, and resulted in a decrease of ERα expression and an elevation of AR in the pancreas measured by Western boltting. The results suggested that TBT inhibited the proliferation and induced the apoptosis of islet cells via multipathways, causing a decrease of relative islet area in the animals treated for 60 days, which could result in a disruption of glucose homeostasis. The different presence of ERs and AR between the islets and exocrine pancreas might be one of reasons causing different effects on cell proliferation.

Testosterone protects against glucotoxicity-induced apoptosis of pancreatic β-cells (INS-1) and male mouse pancreatic islets

Male hypogonadism associates with type 2 diabetes, and T can protect pancreatic β-cells from glucotoxicity. However, the protective mechanism is still unclear. This study thus aims to examine the antiapoptotic mechanism of T in pancreatic β cells cultured in high-glucose medium. T (0.0005-2 μg/mL) was added to INS-1 cells cultured in basal glucose or high-glucose media. Then cellular apoptosis, oxidative stress, and cell viability were measured. Endoplasmic reticulum (ER) stress markers and sensors and the antiapoptotic protein (B-cell lymphoma 2) were investigated by real-time PCR and Western blot analysis. ER stress markers were also measured in male mouse pancreatic islet cultured in similar conditions. T (0.05 and 0.5 μg/mL) did not have any effect on apoptosis and viability of INS-1 cells cultured in basal glucose medium, but it could reduce apoptosis and increase viability of INS-1 cells cultured in high-glucose medium. The protective effect of T is diminished by androgen receptor inhibitor. T (0.05 μg/mL) could significantly reduce nitrotyrosine levels, mRNA, and protein levels of the ER stress markers and sensor those that were induced when INS-1 cells were cultured in high-glucose medium. It could also significantly increase the survival proteins, sarco/endoplasmic reticulum Ca(2+) ATPase-2, and B-cell lymphoma 2 in INS-1 cells cultured in the same conditions. Similarly, it could reduce ER stress markers and increase sarco/endoplasmic reticulum Ca(2+) ATPase protein levels in male mouse pancreatic islets cultured in high-glucose medium. T can protect against male pancreatic β-cell apoptosis from glucotoxicity via the reduction of both oxidative stress and ER stress.

Androgen receptor (AR) positive vs negative roles in prostate cancer cell deaths including apoptosis, anoikis, entosis, necrosis and autophagic cell death

Androgen/androgen receptor (AR) signaling plays pivotal roles in the prostate development and homeostasis as well as in the progression of prostate cancer (PCa). Androgen deprivation therapy (ADT) with anti-androgens remains as the main treatment for later stage PCa, and it has been shown to effectively suppress PCa growth during the first 12-24 months. However, ADT eventually fails and tumors may re-grow and progress into the castration resistant stage. Recent reports revealed that AR might play complicated and even opposite roles in PCa progression that might depend on cell types and tumor stages. Importantly, AR may influence PCa progression via differential modulation of various cell deaths including apoptosis, anoikis, entosis, necrosis, and autophagic cell deaths. Targeting AR may induce PCa cell apoptosis, autophagic cell deaths and programmed necrosis, yet targeting AR may suppress cell deaths via anoikis and entosis that may potentially lead to increased metastasis. These differential functions of AR in various types of PCa cell death might challenge the current ADT with anti-androgens treatment. Further detailed dissection of molecular mechanisms by which AR modulates different PCa cell deaths will help us to develop a better therapy to battle PCa.

The pancreas is altered by in utero androgen exposure: implications for clinical conditions such as polycystic ovary syndrome (PCOS)

Using an ovine model of polycystic ovary syndrome (PCOS), (pregnant ewes injected with testosterone propionate (TP) (100 mg twice weekly) from day (d)62 to d102 of d147 gestation (maternal injection - MI-TP)), we previously reported female offspring with normal glucose tolerance but hyperinsulinemia. We therefore examined insulin signalling and pancreatic morphology in these offspring using quantitative (Q) RT-PCR and western blotting. In addition the fetal pancreatic responses to MI-TP, and androgenic and estrogenic contributions to such responses (direct fetal injection (FI) of TP (20 mg) or diethylstilbestrol (DES) (20 mg) at d62 and d82 gestation) were assessed at d90 gestation. Fetal plasma was assayed for insulin, testosterone and estradiol, pancreatic tissue was cultured, and expression of key β-cell developmental genes was assessed by QRT-PCR. In female d62MI-TP offspring insulin signalling was unaltered but there was a pancreatic phenotype with increased numbers of β-cells (P<0.05). The fetal pancreas expressed androgen receptors in islets and genes involved in β-cell development and function (PDX1, IGF1R, INSR and INS) were up-regulated in female fetuses after d62MI-TP treatment (P<0.05-0.01). In addition the d62MI-TP pancreas showed increased insulin secretion under euglycaemic conditions (P<0.05) in vitro. The same effects were not seen in the male fetal pancreas or when MI-TP was started at d30, before the male programming window. As d62MI-TP increased both fetal plasma testosterone (P<0.05) and estradiol concentrations (P<0.05) we assessed the relative contribution of androgens and estrogens. FI-TP (commencing d62) (not FI-DES treatment) caused elevated basal insulin secretion in vitro and the genes altered by d62MI-TP treatment were similarly altered by FI-TP but not FI-DES. In conclusion, androgen over-exposure alters fetal pancreatic development and β-cell numbers in offspring. These data suggest that that there may be a primary pancreatic phenotype in models of PCOS, and that there may be a distinct male and female pancreas.

Toxicity and carcinogenicity of androstenedione in F344/N rats and B6C3F1 mice

Androstenedione was marketed as a dietary supplement to increase muscle mass during training. Due to concern over long-term use, the NTP evaluated the subchronic and chronic toxicity and carcinogenicity of androstenedione in male and female F344/N rats and B6C3F1 mice. In subchronic studies, dose limiting effects were not observed. A chronic (2-year) exposure by gavage at 10, 20, or 50 mg/kg in rats and male mice, and 2, 10, or 50 mg/kg in female mice (50 mg/kg, maximum feasible dose) was conducted. Increased incidences of lung alveolar/bronchiolar adenoma and carcinoma occurred in the 20 mg/kg male rats and increases in mononuclear cell leukemia occurred in the 20 and 50 mg/kg female rats, which may have been related to androstenedione administration. In male and female mice, androstenedione was carcinogenic based upon a significant increase in hepatocellular tumors. A marginal increase in pancreatic islet cell adenomas in male (50 mg/kg) and female (2, 10, 50 mg/kg) mice was considered to be related to androstenedione administration. Interestingly, incidences of male rat Leydig cell adenomas and female rat mammary gland fibroadenomas decreased. In conclusion, androstenedione was determined to be carcinogenic in male and female mice, and may have been carcinogenic in rats.

BCL2L10 protein regulates apoptosis/proliferation through differential pathways in gastric cancer cells

The reason for and consequences of BCL2L10 down-regulation in gastric carcinoma are poorly understood. Our aim was to investigate the function of the protein BCL2L10 in gastric carcinoma. We investigated BCL2L10 expression using quantitative real-time PCR and immunoblotting. The methylation status of the BCL2L10 gene promoter was examined by bisulphite sequencing in fresh gastric normal and carcinoma tissues. We studied apoptosis and proliferation regulation in gastric cancer cell lines using flow cytometry, fluorescence staining, murine xenografting and immunoblotting. Pathway inhibitors were applied to confirm the major pathways involved in apoptosis or proliferation regulation. We observed significant correlations between lower BCL2L10 expression and CpG island hypermethylation of the BCL2L10 gene promoter in gastric carcinoma, apoptosis induced by over-expressed BCL2L10 through mitochondrial pathways, and proliferation accelerated by BCL2L10 siRNA via the PI3K-Akt signalling pathway in gastric cancer cell lines. The pro-apoptotic effect of BCL2L10 and growth promotion by BCL2L10 siRNA in gastric cancer cells suggest that it may be a tumour suppressor.

Prenatal androgen exposure programs metabolic dysfunction in female mice

Polycystic ovary syndrome (PCOS) is a common fertility disorder with metabolic sequelae. Our laboratory previously characterized reproductive phenotypes in a prenatally androgenized (PNA) mouse model for PCOS. PNA mice exhibited elevated testosterone and LH levels, irregular estrous cycles, and neuroendocrine abnormalities suggesting increased central drive to the reproductive system. In this study, we examined metabolic characteristics of female PNA mice. PNA mice exhibited increased fasting glucose and impaired glucose tolerance (IGT) that were independent of age and were not associated with changes in body composition or peripheral insulin sensitivity. IGT was associated with defects in pancreatic islet function leading to an impaired response to high glucose, consistent with impaired insulin secretion. Exposure of isolated pancreatic islets to androgen in vitro demonstrated an impaired response to glucose stimulation similar to that in PNA mice, suggesting androgens may have activational in addition to organizational effects on pancreatic islet function. PNA mice also exhibited increased size of visceral adipocytes, suggesting androgen-programed differences in adipocyte differentiation and/or function. These studies demonstrate that in addition to causing reproductive axis abnormalities, in utero androgen exposure can induce long-term metabolic alterations in female mice.

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.