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Introduction: Previous research has indicated that a lipid-independent pathogenic mechanism plays a role in androgen-induced hepatic insulin resistance where liver androgen receptors may play a role in modulating disease. Consequently, this study aims to investigate the pathophysiology of high fructose diet (HFrD) induced dysglycemia in male and female liver androgen receptor knockout (LivARKO) mice. Andrisse et al 2021 showed that deleting the liver androgen receptor prevented female mice from developing hyperandrogenemia (HA)-induced insulin resistance. From this, we asked the question, does LivARKO prevent HFrD induced dysglycemia? Hypothesis: It was hypothesized that HFrD LivARKO female mice would display impaired whole body glucose metabolism in comparison to the Control diet fed LivARKO female mice, suggesting that AR does not play a significant role in regulating HFrD-induced dysglycemia.Methods: We performed insulin tolerance tests (ITT), glucose tolerance tests (GTT), pyruvate tolerance tests (PTT), and glucose stimulated insulin secretion (GSIS) tests on LivARKO female mice fed a high fat diet (HFD) or a control diet (CD) (from Research Diets Inc) during months 1 or 2 after starting the diet. Results: After 1-month, LivARKO female mice fed a Control diet had impaired glucose tolerance compared to LivARKO-HFrD female mice; however, after 2-months, the LivARKO-HFrD female mice displayed impaired glucose tolerance above that of the Control diet LivARKO female mice. LivARKO female mice fed a high fructose diet (HFrD) did not display increased fasting insulin levels compared to LivARKO female mice on a control diet. HFrD LivARKO mice did not display any increase in GSIS at 15-min or 30-min. Conclusion: These findings suggest that LivARKO delayed the onset of HFrD-Induced dysglycemia in female mice. Further research may consist of molecular data to elucidate the mechanistic pathways involved in these whole body phenotypes observed. The cellular molecular regulation of differing mechanisms of insulin resistance. 1R01DK126892-01A1 This is the full abstract presented at the American Physiology Summit 2023 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

ContextNonalcoholic fatty liver disease (NAFLD) describes a spectrum of liver damage due to excessive hepatic lipid accumulation. Recent research has demonstrated a high prevalence of NAFLD in women with polycystic ovary syndrome (PCOS).ResultsStrong associations independent of body mass index (BMI) have been found between high androgen levels characteristic of PCOS, as well as insulin resistance, and the presence of NAFLD in these women, suggesting that these factors contribute to liver injury more significantly than obesity. Current studies indicate the occurrence of NAFLD in normal weight women with PCOS in addition to the commonly researched women who are overweight and obese. While the majority of studies address NAFLD in adult, premenopausal women (ages 25-40 years), the occurrence of NAFLD in young and adolescent women has gone largely unaddressed. Research in this field lacks diversity; a majority of studies either focus on populations of White women or are missing demographic information entirely.ConclusionsFuture studies should include larger, more racially and ethnically inclusive populations and particular attention should be paid to how excess androgens and insulin resistance contribute to the increased risk of NAFLD seen in women with PCOS of varying weights, ages, and ethnicities.Objective and MethodsHere, we review NAFLD in women with PCOS with subsections focused on the impact of hyperandrogenism, BMI, insulin resistance and age. Most notably, we present the most up-to-date racially and ethnically diverse worldwide prevalence of NAFLD in women with PCOS compared with women without PCOS (51.56% vs 29.64%, P < .001, respectively).

Hyperandrogenemia (HA) is a hallmark of polycystic ovary syndrome (PCOS) and is an integral element of non-alcoholic fatty liver disease (NALFD) in females. Administering low-dose dihydrotestosterone (DHT) induced a normal weight PCOS-like female mouse model displaying NAFLD. The molecular mechanism of HA-induced NAFLD has not been fully determined. We hypothesized that DHT would regulate hepatic lipid metabolism via increased SREBP1 expression leading to NAFLD. We extracted liver from control and low-dose DHT female mice; and performed histological and biochemical lipid profiles, Western blot, immunoprecipitation, chromatin immunoprecipitation, and real-time quantitative PCR analyses. DHT lowered the 65 kD form of cytosolic SREBP1 in the liver compared to controls. However, DHT did not alter the levels of SREBP2 in the liver. DHT mice displayed increased SCAP protein expression and SCAP-SREBP1 binding compared to controls. DHT mice exhibited increased AR binding to intron-8 of SCAP leading to increased SCAP mRNA compared to controls. FAS mRNA and protein expression was increased in the liver of DHT mice compared to controls. p-ACC levels were unaltered in the liver. Other lipid metabolism pathways were examined in the liver, but no changes were observed. Our findings support evidence that DHT increased de novo lipogenic proteins resulting in increased hepatic lipid content via regulation of SREBP1 in the liver. We show that in the presence of DHT, the SCAP-SREBP1 interaction was elevated leading to increased nuclear SREBP1 resulting in increased de novo lipogenesis. We propose that the mechanism of action may be increased AR binding to an ARE in SCAP intron-8.

Objective: We hypothesize that in women experiencing obesity and PCOS, the women with higher levels of free androgen index will display more dysregulation in the insulin signaling pathway in adipose tissue. More specifically, we believe that visceral more than subcutaneous adipose tissue in the women in the study will display more dysregulation; and lastly that bariatric surgery will alleviate insulin signaling dysregulation. Methods: Here, we performed molecular analyses (Western blots and qPRC) exploring the insulin signaling pathway in visceral and subcutaneous (SubQ) adipose tissue from women with obesity and PCOS undergoing RYGB bariatric surgery; and SubQ WAT from women with obesity and PCOS at baseline and six-months after medical intervention with metformin (MTF) . Results: Subcutaneous (SubQ) white adipose tissue (WAT) displayed a trending (p=0.2) but non-significant increase in p-ACC compared to visceral WAT from women with PCOS and obesity pre-bariatric surgery. Six months of MTF increased p-ACC in SubQ WAT by 5-fold compared to zero months (baseline) in women with PCOS and obesity. IR displayed similar expression in the visceral compared to SubQ WAT in women with PCOS and obesity pre-bariatric surgery. IR expression increased by 20-fold at 6-months of MTF compared to baseline in SubQ WAT of women with PCOS and obesity. Phosphorylated forkhead box 01 (p-FOXO1) displayed similar expression in the visceral compared to SubQ WAT in women with PCOS and obesity. However, p-FOXO1 was decreased at 6-months of MTF compared to baseline in women with PCOS and obesity. p-AKT levels were similar in visceral compared to SubQ WAT in women with PCOS and obesity pre-bariatric surgery. However, p-AKT levels were significantly increased by 4-fold at 6-months of MTF compared to 0-months in women with PCOS and obesity. Conclusion: None of the insulin signaling intermediates measured were altered in visceral compared to SubQ in women with obesity and PCOS. Disclosure S. Andrisse: None.

Background Recently an androgen-induced obesity-independent mechanism of insulin resistance in a mouse model mimicking lean polycystic ovary syndrome (PCOS) was discovered. To date there is little to no data on the mechanism of insulin resistance or molecular insulin signaling in adipose tissue of women with PCOS undergoing Vertical Sleeve Gastrectomy (VSG). Does the mechanism of androgen receptor (AR)-mediated regulation of insulin signaling seen in the lean PCOS mouse model occur in adipose tissue of women with obesity and PCOS? Objective We hypothesize that in women with obesity and PCOS, those with higher levels of free androgen index will display more dysregulation in the insulin signaling pathway in adipose tissue. More specifically, we believe that visceral more than subcutaneous adipose tissue in the women in the study will display more dysregulation; and lastly that VSG will alleviate insulin signaling dysregulation. Briefly, insulin activates insulin receptor (IR) which leads to activation of phospho-AKT which increases phosphorylated forkhead box 01 (p-FOXO1, gluconeogenesis regulation) and transcriptionally regulates acetyl co-A carboxylase (ACC, de novo lipogenesis (DNL) regulation). Methods This is a nested mechanistic study within a randomised controlled clinical trial. We performed molecular analyses (Western blots for protein and qPRC for mRNA expression, respectively, n = 3-4/group) exploring intermediates in the insulin signaling pathway (IR, p-AKT, p-FOXO1, and ACC) in (i) visceral and subcutaneous (SubQ) adipose tissue from women with obesity and PCOS before VSG bariatric surgery (n = 3/group); and (ii) SubQ WAT from women with obesity and PCOS at baseline and six-months after medical intervention with metformin (MTF) and lifestyle modification. Results Subcutaneous (SubQ) white adipose tissue (WAT) displayed similar levels of p-ACC compared to visceral WAT from women pre-VSG. Six months of medical care increased p-ACC in SubQ WAT by 5-fold compared to baseline. IR displayed similar expression in the visceral compared to SubQ WAT in women pre-VSG. IR expression increased by 20-fold at 6-months of medical care compared to baseline in SubQ WAT. p-FOXO1 displayed similar expression in the visceral compared to SubQ WAT. However, p-FOXO1 was decreased at 6-months of medical care compared to baseline. p-AKT levels were similar in visceral compared to SubQ WAT pre-VSG. However, p-AKT levels were significantly increased by 4-fold at 6-months of medical care compared to baseline. Conclusion None of the insulin signaling intermediates measured were different in visceral compared to SubQ in women with obesity and PCOS. Additionally, the findings indicated lowered DNL, lowered regulation of gluconeogenic genes and thus lowered gluconeogenesis, and increased insulin action in SubQ WAT in women with obesity and PCOS after 6-months of medical care. Presentation: Sunday, June 12, 2022 12:30 p.m. - 2:30 p.m.

Androgen excess is one of the most common endocrine disorders of reproductive-aged women, affecting up to 20% of this population. Women with elevated androgens often exhibit hyperinsulinemia and insulin resistance. The mechanisms of how elevated androgens affect metabolic function are not clear. Hyperandrogenemia in a dihydrotestosterone (DHT)-treated female mouse model induces whole body insulin resistance possibly through activation of the hepatic androgen receptor (AR). We investigated the role of hepatocyte AR in hyperandrogenemia-induced metabolic dysfunction by using several approaches to delete hepatic AR via animal-, cell-, and clinical-based methodologies. We conditionally disrupted hepatocyte AR in female mice developmentally (LivARKO) or acutely by tail vein injection of an adeno-associated virus with a liver-specific promoter for Cre expression in AR(fl/fl) mice (adLivARKO). We observed normal metabolic function in littermate female Control (AR(fl/fl)) and LivARKO (AR(fl/fl); Cre(+/−)) mice. Following chronic DHT treatment, female Control mice treated with DHT (Con-DHT) developed impaired glucose tolerance, pyruvate tolerance, and insulin tolerance, not observed in LivARKO mice treated with DHT (LivARKO-DHT). Furthermore, during an euglycemic hyperinsulinemic clamp, the glucose infusion rate was improved in LivARKO-DHT mice compared to Con-DHT mice. Liver from LivARKO, and primary hepatocytes derived from LivARKO, and adLivARKO mice were protected from DHT-induced insulin resistance and increased gluconeogenesis. These data support a paradigm in which elevated androgens in females disrupt metabolic function via hepatic AR and insulin sensitivity was restored by deletion of hepatic AR.

Androgen excess is one of the most common endocrine disorders of reproductive-aged women, affecting up to 20% of this population. Women with elevated androgens often exhibit hyperinsulinemia and insulin resistance. The mechanisms of how elevated androgens affect metabolic function are not clear. Hyperandrogenemia in a dihydrotestosterone (DHT)-treated female mouse model induces whole body insulin resistance possibly through activation of the hepatic androgen receptor (AR). We investigated the role of hepatocyte AR in hyperandrogenemia-induced metabolic dysfunction by using several approaches to delete hepatic AR via animal-, cell-, and clinical-based methodologies. We conditionally disrupted hepatocyte AR in female mice developmentally (LivARKO) or acutely by tail vein injection of an adeno-associated virus with a liver-specific promoter for Cre expression in ARfl/fl mice (adLivARKO). We observed normal metabolic function in littermate female Control (ARfl/fl) and LivARKO (ARfl/fl; Cre+/-) mice. Following chronic DHT treatment, female Control mice treated with DHT (Con-DHT) developed impaired glucose tolerance, pyruvate tolerance, and insulin tolerance, not observed in LivARKO mice treated with DHT (LivARKO-DHT). Further, during an euglycemic hyperinsulinemic clamp, the glucose infusion rate was improved in LivARKO-DHT mice compared to Con-DHT mice. Liver from LivARKO, and primary hepatocytes derived from LivARKO, and adLivARKO mice were protected from DHT-induced insulin resistance and increased gluconeogenesis. These data support a paradigm in which elevated androgens in females disrupt metabolic function via hepatic AR and insulin sensitivity was restored by deletion of hepatic AR.

Polycystic ovarian syndrome (PCOS) is a hormonal disorder with insulin resistance (IR) and hyperandrogenism (HA) as drivers of the condition. PCOS women have an increased risk of developing nonalcoholic fatty liver disease (NAFLD). Our lab explores NAFLD in PCOS through a mouse model with a liver androgen receptor (AR) knockout (LivARKO). The role of AR in high-fat diet (HFD) induced metabolic disease is not fully understood. We hypothesized that LivARKO would cause dysglycemia in males but protect from dysglycemia in females. To test the hypothesis, we collected data from mice fed a HFD or a caloric adjusted control diet (CD) over the course of two months. We performed glucose tolerance (GTT), insulin tolerance (ITT), and pyruvate tolerance (PTT) tests. At 1-month, HFD female LivARKO mice displayed no difference in glucose tolerance compared to CD LivARKO female mice, suggesting that at one month LivARKO is protecting female mice from HFD-induced metabolic dysfunction. HFD male LivARKO mice displayed impaired glucose tolerance (IGT) compared to CD LivARKO mice. Thus, LivARKO was not protective against HFD-induced glucose metabolic dysfunction in male mice. At 2-months, HFD showed IGT compared to Control diet in male and female LivARKO mice, suggesting that LivARKO slowed the progression to metabolic disease in female mice but did not fully stop it. HFD male and female LivARKO mice did not display significant changes in insulin tolerance at 1-month compared to CD mice. HFD male and female LivARKO mice showed impaired pyruvate tolerance starting at 1-month and continuing at 2-months compared to CD LivARKO mice. The impairment was significantly greater in male mice. In conclusion, we found that it took LivARKO female mice longer to show dysglycemia from HFD than male LivARKO mice. Thus, in females, LivARKO slowed the progression to metabolic disease, but did not fully stop it. The impaired PTT suggests the effects of HFD may alter hepatic gluconeogenic regulation. Disclosure T. R. Oliver: None. A. Osei-ntansah: None. S. Andrisse: None. T. Lofton: None. C. Falzarano: None. Funding National Science Foundation (HRD-1931045)

Previous research has indicated that a lipid-independent pathogenic mechanism plays a role in androgen-induced hepatic insulin resistance where liver androgen receptors may play a role in modulating disease. Consequently, this study aims to investigate the pathophysiology of high fat diet (HFD) induced dysglycemia and hepatic insulin resistance in male and female liver androgen receptor knockout (LivARKO) mice. We performed insulin tolerance tests (ITT), glucose tolerance tests (GTT), and pyruvate tolerance tests (PTT) on LivARKO male and female mice fed a high fat diet (HFD) or a control diet (CD) (from Research Diets Inc) during months 1 or 2 after starting the diet. Two-months on the CD showed significantly enhanced glucose tolerance (EGT) compared to 1-month on CD in both male and female LivARKO mice. This EGT phenotype was the same and equally as significant in males vs. females. Two-months on CD showed impaired insulin sensitivity (IIS) compared to 1-month on CD in male and female LivARKO mice. This IIS was significantly greater in female mice. Two-months on the CD displayed enhanced pyruvate tolerance compared to 1-month on the CD in male and female LivARKO mice. Two-months compared to 1-month on HFD displayed no significant difference in glucose tolerance in male and female LivARKO mice. Two-months on HFD showed impaired insulin sensitivity compared to 1-month in female but not male LivARKO mice. Pyruvate tolerance was not changed from 1- to 2-months on HFD in male or female LivARKO mice. In the CD mice, we see EGT but IIS. This suggests that insulin action is decreased. The enhanced pyruvate tolerance in CD mice suggests that the control diet lowers gluconeogenesis. Why the control diet is altering glucose metabolism from 1-2 months is still a question to be investigated. In conclusion, we show that 1- vs. 2-months on HFD showed no change in glucose metabolism in male and a slight change in female LivARKO mice. Disclosure A. Osei-ntansah: None. T. R. Oliver: None. C. Falzarano: None. T. Lofton: None. S. Andrisse: None. Funding National Science Foundation (HRD-1931045); Robert Wood Johnson Foundation

Context Polycystic ovary syndrome (PCOS) is common and associated with metabolic syndrome. In the general population, metabolic disease varies by race and ethnicity. Objective This work aimed to examine in depth the interaction of race and ethnicity with PCOS-related metabolic disease in adolescent youth. Methods A secondary analysis was conducted of data from girls (age 12-21 years) with overweight or obesity (> 90 body mass index [BMI] percentile) and PCOS. Measurements included fasting hormone and metabolic measures, a 2-hour oral glucose tolerance test (OGTT), and magnetic resonance imaging for hepatic fat. Groups were categorized by race or ethnicity. Results Participants included 39 non-Hispanic White (NHW, age 15.7 ± 0.2 years; BMI 97.7 ± 0.2 percentile), 50 Hispanic (HW, 15.2 ± 0.3 years; 97.9 ± 0.3 percentile), and 12 non-Hispanic Black (NHB, 16.0 ± 0.6 years; 98.6 ± 0.4 percentile) adolescents. Hepatic markers of insulin resistance were worse in NHW, including lower sex hormone–binding globulin and higher triglycerides over high-density lipoprotein cholesterol (TGs/HDL-C) ratio (P = .002 overall, HW vs NHB [P = .009] vs NHW [P = 0.020]), although homeostasis model assessment of estimated insulin resistance was worst in NHB (P = .010 overall, NHW vs NHB P = .014). Fasting and 2-hour OGTT glucose were not different between groups, although glycated hemoglobin A1c (HbA1c) was lowest in NHW (overall P Conclusion Adolescents with PCOS appear to show similar racial and ethnic variation to the general population in terms of metabolic disease components.

Hyperandrogenemia (HA) and insulin resistance are hallmarks of polycystic ovary syndrome (PCOS). These hallmarks are also integral elements of nonalcoholic liver disease (NALFD). Administering low dose dihydrotestosterone (DHT) induced a lean female mouse model with a PCOS-like phenotype. The molecular mechanism of HA-induced NAFLD has not been determined. We hypothesized that low dose DHT would interrupt hepatic lipid metabolism leading to NAFLD. We extracted white adipose tissue (WAT), liver, and skeletal muscle from control and low dose DHT female mice; and performed Western blot and real-time quantitative PCR (qRT-PCR) analysis of lipogenic intermediates. Low-dose DHT lowered the active form of cytosolic SREBP1 in the liver and WAT compared to controls. Additionally, low dose DHT increased inactive SREBP1 in the liver. However, DHT did not alter the levels of the active and inactive forms of SREBP2 in the liver and WAT. DHT increased SCAP protein expression and SCAP-SREBP1 binding, which helps activate SREBP. Regarding lipogenic enzymes, FAS mRNA and protein expression was increased in liver of DHT mice. p-ACC levels were unaltered in liver but decreased in WAT. Other lipid metabolism pathways were examined in liver and WAT but no changes were observed. Taken together, our findings support the hypothesis that cytosolic SREBP1 decreased due to its translocation to the nucleus, where it upregulated lipogenic mRNA expression. We showed that low-dose DHT increased SCAP-SREBP-1 association promoting the activation and translocation of SREBP1 from the cytosol to the nucleus to influence lipogenic gene expression leading to increased lipogenesis contributing to NAFLD. Disclosure S. Andrisse: None. Funding Robert Wood Johnson Foundation (74250); Eunice Kennedy Shriver National Institute of Child Health and Human Development (K23HD095075)

Background: Polycystic ovary syndrome (PCOS) affects up to 15% of women and is associated with a multitude of metabolic complications including insulin resistance, type 2 diabetes, cardiovascular disease, and hepatic steatosis. In the general population, metabolic disease rates vary by race and ethnicity. The interaction of race and ethnicity with PCOS-related metabolic disease in adolescent youth has not been extensively examined. Methods: Secondary analysis of data from overweight and obese (>90 BMI%ile) adolescent (12-21 years) female participants with PCOS enrolled across 4 protocols. Measurements included fasting hormone and metabolic measures, a 2-hour oral glucose tolerance test and MRI for hepatic fat. Groups were compared by ANOVA, with and without correction for BMI or chi-square tests for proportions. Results: Participants included 39 white (NHW 15.7±0.2 years; 97.7±0.2 BMI%ile), 50 Hispanic (15.2±0.3 years; 97.9±0.3 BMI%ile) and 12 black (NHB 16.0±0.6 years; 98.6±0.4 BMI%ile) adolescents. BMI%ile was different between groups (p=0.04), but age of menarche, free testosterone and hirsutism severity were not. Hepatic markers of insulin resistance were worse in Hispanic youth, including lower sex hormone binding globulin and TG/HDL ratio (p

Hyperandrogenemia (HA) and insulin resistance (IR) are hallmarks of polycystic ovary syndrome (PCOS), a common endocrine disorder that affects 1 in 10 women. These hallmarks are also integral elements of non-alcoholic liver disease (NALFD), a disorder that is common in women with PCOS. Administering low dose dihydrotestosterone (DHT) induced a lean female mouse model with a PCOS-like phenotype, displaying IR and NAFLD. The molecular mechanism of HA-induced NAFLD has not been determined. We hypothesized that low dose DHT would interrupt hepatic lipid metabolism leading to NAFLD. To investigate the role of androgens on the master regulator of lipogenesis, sterol regulatory element-binding protein 1 (SREBP1), we extracted white adipose tissue (WAT), liver, and skeletal muscle from wild-type, control and low dose DHT female mice; and performed Western blot and real-time quantitative PCR (qRT-PCR) analysis of lipogenic intermediates of the tissue homogenates. Low-dose DHT lowered the active form of cytosolic SREBP1 in the liver and WAT compared to controls. Additionally, low dose DHT lowered inactive SREBP1 in the liver. However, the condition did not alter the levels of the active and inactive forms of SREBP2 in the liver and WAT, though the active form was lowered in skeletal muscle. Further, p-ACC levels were unaltered in liver and WAT. FAS levels were unchanged in WAT and skeletal muscle. Taken together, our findings support the hypothesis that cytosolic SREBP1 decreased due to its translocation to the nucleus, where it regulates lipogenic protein levels. We speculate that low-dose DHT promotes the translocation of SREBP1 from the cytosol to the nucleus to influence lipogenic gene expression leading to increased lipogenesis contributing to NAFLD.

Hyperandrogenemia (HA) and insulin resistance are hallmarks of polycystic ovary syndrome (PCOS). These hallmarks are also integral elements of non-alcoholic fatty liver disease (NALFD). Administering low dose dihydrotestosterone (DHT) induced a lean PCOS-like female mouse model. The molecular mechanism of HA-induced NAFLD has not been determined. We hypothesized that low dose DHT would interrupt hepatic lipid metabolism leading to NAFLD. We extracted white adipose tissue (WAT), liver, and skeletal muscle from control and low dose DHT female mice; and performed histological and biochemical lipid profiles, Western blot, immunoprecipitation, chromatin immunoprecipitation, and real-time quantitative PCR analyses. DHT lowered the 65 kD form of cytosolic SREBP1 in the liver and WAT compared to controls. However, DHT did not alter the levels of the active and inactive forms of SREBP2 in the liver and WAT. DHT increased SCAP protein expression and SCAP-SREBP1 binding via AR binding to intron-8 of SCAP leading to increased SCAP mRNA. FAS mRNA and protein expression was increased in liver of DHT mice. p-ACC levels were unaltered in liver but decreased in WAT. Other lipid metabolism pathways were examined in liver and WAT, but no changes were observed. Our findings suggest that DHT increased de novo lipogenic proteins resulting in increased NAFLD via regulation of SREBP1 in liver. We show that in the presence of DHT the SCAP-SREBP1 interaction is elevated leading to increased nuclear SREBP1 resulting in increased de novo lipogenesis. We propose that the mechanism of action is increased AR binding to an ARE in SCAP intron-8.

Hyperandrogenemia (HA) and insulin resistance (IR) are hallmarks of polycystic ovary syndrome (PCOS), a common endocrine disorder that affects 1 in 10 women. These hallmarks are also integral elements of nonalcoholic liver disease (NALFD), a disorder that is common in women with PCOS. Administering low dose dihydrotestosterone (DHT) induced a lean female mouse model with a PCOS-like phenotype, displaying IR and NAFLD. The molecular mechanism of HA-induced NAFLD has not been determined. We hypothesized that low dose DHT would interrupt hepatic lipid metabolism leading to NAFLD. To investigate the role of androgens on the master regulator of lipogenesis, sterol regulatory element-binding protein 1 (SREBP-1), we extracted white adipose tissue (WAT), liver, and skeletal muscle from wild type, control and low dose DHT female mice; and performed Western blot and real-time quantitative PCR (qRT-PCR) analysis of lipogenic intermediates of the tissue homogenates. Low-dose DHT lowered the active form of cytosolic SREBP1 in the liver and WAT compared to controls. Additionally, low-dose DHT lowered inactive SREBP1 in the liver. However, the condition did not alter the levels of the active and inactive forms of SREBP2 in the liver and WAT, though the active form was lowered in skeletal muscle. Further, p-ACC levels were unaltered in liver and WAT. FAS levels were unchanged in WAT and skeletal muscle. Taken together, our findings support the hypothesis that cytosolic SREBP1 decreased due to its translocation to the nucleus, where it regulates lipogenic protein levels. We speculate that low-dose DHT promotes the translocation of SREBP-1 from the cytosol to the nucleus to influence lipogenic gene expression leading to increased lipogenesis contributing to NAFLD. Disclosure S. Andrisse: None.

Polycystic ovary syndrome (PCOS) affects 10% of women and is hallmarked by hyperandrogenemia (HA), which is also a component of non-alcoholic fatty liver disease (NAFLD). In this project, we aimed to investigate how androgen and androgen receptor (AR) impact a key player of lipogenesis, sterol regulatory element-binding protein 1 (SREBP1). To this end, skeletal muscle from lean, female wild type mice and mice administered dihydrotestosterone (DHT) for one month were extracted and analyzed to determine the effect of low dose DHT on lipogenic cytosolic protein and gene expression. We performed Western blot and real-time quantitative polymerase chain reaction (qRT-PCR) analysis of lipogenic intermediates in homogenates of an energy storage tissue. Skeletal muscle was used as a control. Low-dose DHT lowered the active form of cytosolic SREBP-2 in skeletal muscle. However, FAS and p-ACC protein and mRNA expression levels were unchanged in skeletal muscle. The results indicate that SREBP-2 is the primary SREBP isoform in skeletal muscle but that it is not playing a role in DHT-induced lipogenic gene expression or NAFLD. Thank you to HUCM, JHUSOM, and Georgetown University Medical Center (GUMC) for supporting this work.

Women with elevated androgen often exhibit hyperinsulinemia and insulin resistance. Many models have been created to produce metabolic dysfunction by manipulating androgen levels. Previously we reported that hyperandrogenemia produced by implantation of a DHT pellet may induce whole body insulin resistance through hepatic androgen receptor (AR) in vitro. Therefore, we conditionally disrupted the hepatic AR both developmentally (by breeding the albumin-CRE mouse (alb-CRE; liver-specific Cre expression) with ARfl/fl mice (LivARKO)) and acutely (by tail vein injection in ARfl/fl mice of adeno-associated virus with albumin promoter driven Cre vector (adLivARKO)). Impaired glucose tolerance, pyruvate tolerance, and insulin tolerance were prevented in both LivARKO-DHT and adLivARKO-DHT mice compared to control mice treated with DHT (ARfl/fl; cre-; Con-DHT) mice. Further, the glucose infusion rate is significantly reduced in LivARKO-DHT mice compared to Con-DHT mice as measured during hyperinsulinemia-euglycemia clamp suggesting improved insulin-induced glucose disposal. We observed that primary hepatocytes treated with DHT from both women and female mice showed reduced PI3K-pAKT and pFOXO1 activation by insulin, and increased ex vivo glucose production. LivARKO primary hepatocytes were resistant to DHT induced attenuated insulin signaling and increased gluconeogenesis (ex vivo) and this was confirmed in LivARKO in vivo. These data support a paradigm in which in females, elevated androgen disrupts metabolic function via hepatic AR.

Abstract: Hyperandrogenemia (HA) and insulin resistance (IR) are hallmarks of polycystic ovary syndrome (PCOS), a common endocrine disorder that affects roughly 1 in 5 women, according to the Rotterdam criteria. These hallmarks are also integral elements of non-alcoholic fatty liver disease (NALFD), a disorder that is common in women with PCOS. In lean female mouse models of dihydrotestosterone (DHT)-induced PCOS, a low dose of DHT promotes IR and hepatic lipogenesis via the androgen receptor (AR), thus resulting in NAFLD (1). However, the molecular mechanism of HA-induced NAFLD has not been determined. We hypothesized that a low dose of DHT would interrupt hepatic lipid metabolism leading to NAFLD. To investigate the role of androgen and AR on a master regulator of lipogenesis, sterol regulatory element-binding protein 1 (SREBP-1), we extracted white adipose tissue (WAT) from lean, female wild-type mice and lean PCOS female mice, aka "DHT mice." Then we analyzed the effect of low-dose DHT on lipogenic protein and gene expression as a control to low-dose DHT's impact on the liver. We accomplished this by performing Western blots and real-time quantitative polymerase chain reaction (qRT-PCR) analysis of the cytosolic lipogenic proteins and gene expression of WAT. A low dose of DHT lowered the active form of SREBP-1 in DHT mice in comparison to the control mice, but there was no significant change in fatty acid synthase (FAS), acetyl-CoA carboxylase (ACC), phosphorylated ACC (p-ACC), and the active and inactive forms of SREBP-2. We speculate that the low-dose DHT promotes the translocation of SREBP-1 from the cytosol to the nucleus to influence lipogenic gene expression leading to increased lipogenesis contributing to NAFLD. (1) Andrisse et al., Endocrinology. 2017 Mar 1;158(3):531-544.

Literature reports suggest that ataxia telangiectasia mutated (ATM) can activate the AMP-activated protein kinase (AMPK), a protein that can stimulate glucose transport in skeletal muscle. We hypothesized that 5-aminoimidazole-4-carboxamide ribonucleotide (AICAR), an AMPK activator, would increase glucose transport in mouse extensor digitorum longus (EDL) muscles in an ATM-dependent manner. AICAR-stimulated glucose transport was prevented by the ATM inhibitor KU-55933 despite normal stimulation of AMPK phosphorylation. Consistent with this, AICAR caused AMPK phosphorylation but not an increase of glucose transport in ATM-deficient (ATM−/−) muscles. S231 of TBC1D1 matches the sequence motif of ATM substrates, and phosphorylation of this site is known to inhibit TBC1D1 and lead to increased glucose transport. Accordingly, we assessed TBC1D1 phosphorylation and found that AICAR-stimulated phosphorylation of TBC1D1 at S231 did not occur in ATM−/− muscles. However, activation of ATM without activation of AMPK was insufficient to increase TBC1D1 phosphorylation. The data suggest that ATM plays a role in AICAR-stimulated glucose transport downstream of AMPK.

Hyperandrogenemia and hyperinsulinemia are believed to play prominent roles in polycystic ovarian syndrome (PCOS). We explored the effects of low-dose dihydrotestosterone (DHT), a model of PCOS, on insulin signaling in metabolic and reproductive tissues in a female mouse model. Insulin resistance in the energy storage tissues is associated with type 2 diabetes. Insulin signaling in the ovaries and pituitary either directly or indirectly stimulates androgen production. Energy storage and reproductive tissues were isolated and molecular assays were performed. Livers and white adipose tissue (WAT) from DHT mice displayed lower mRNA and protein expression of insulin signaling intermediates. However, ovaries and pituitaries of DHT mice exhibited higher expression levels of insulin signaling genes/proteins. Insulin-stimulated p-AKT levels were blunted in the livers and WAT of the DHT mice but increased or remained the same in the ovaries and pituitaries compared with controls. Glucose uptake decreased in liver and WAT but was unchanged in pituitary and ovary of DHT mice. Plasma membrane GLUTs were decreased in liver and WAT but increased in ovary and pituitary of DHT mice. Skeletal muscle insulin-signaling genes were not lowered in DHT mice compared with control. DHT mice did not display skeletal muscle insulin resistance. Insulin-stimulated glucose transport increased in skeletal muscles of DHT mice compared with controls. DHT mice were hyperinsulinemic. However, the differential mRNA and protein expression pattern was independent of hyperinsulinemia in cultured hepatocytes and pituitary cells. These findings demonstrate a differential effect of DHT on the insulin-signaling pathway in energy storage vs. reproductive tissues independent of hyperinsulinemia.

In skeletal muscle cells, GLUT1 is responsible for a large portion of basal uptake of glucose and dehydroascorbic acid, both of which play roles in antioxidant defense. We hypothesized that conditions that would decrease GLUT1-mediated transport would cause increased reactive oxygen species (ROS) levels in L6 myoblasts, while conditions that would increase GLUT1-mediated transport would result in decreased ROS levels. We found that the GLUT1 inhibitors fasentin and phloretin increased the ROS levels induced by antimycin A and the superoxide generator pyrogallol. However, indinavir, which inhibits GLUT4 but not GLUT1, had no effect on ROS levels. Ataxia telangiectasia mutated (ATM) inhibitors and activators, previously shown to inhibit and augment GLUT1-mediated transport, increased and decreased ROS levels, respectively. Mutation of an ATM target site on GLUT1 (GLUT1-S490A) increased ROS levels and prevented the ROS-lowering effect of the ATM activator doxorubicin. In contrast, expression of GLUT1-S490D lowered ROS levels during challenge with pyrogallol, prevented an increase in ROS when ATM was inhibited, and prevented the pyrogallol-induced decrease in insulin signaling and insulin-stimulated glucose transport. Taken together, the data suggest that GLUT1 plays a role in regulation of ROS and could contribute to maintenance of insulin action in the presence of ROS., Highlights • Inhibition of GLUT1, but not inhibition of GLUT4, increases ROS levels in myoblasts. • Mutation of an ATM target site on GLUT1 to alanine (GLUT1-S490A) increases ROS. • The ATM activator doxorubicin decreases ROS except in cells that express GLUT1-S490A. • Inhibition of ATM increases ROS except in cells transfected with GLUT1S490D. • Expression of GLUT1-S490D protects cells against ROS-mediated insulin resistance.

Androgen excess in women is associated with metabolic dysfunction (e.g., obesity, hyperinsulinemia, insulin resistance, and increased risk of type 2 diabetes) and reproductive dysfunction (e.g., polycystic ovaries, amenorrhea, dysregulated gonadotropin release, and infertility). We sought to identify the effects of androgen excess on glucose metabolic dysfunction and the specific mechanisms of action by which androgens are inducing pathology. We developed a mouse model that displayed pathophysiological serum androgen levels with normal body mass/composition to ensure that the phenotypes were directly from androgens and not an indirect consequence of obesity. We performed reproductive tests, metabolic tests, and hormonal assays. Livers were isolated and examined via molecular, biochemical, and histological analysis. Additionally, a low-dose dihydrotestosterone (DHT) cell model using H2.35 mouse hepatocytes was developed to study androgen effects on hepatic insulin signaling. DHT mice demonstrated impaired estrous cyclicity; few corpora lutea in the ovaries; glucose, insulin, and pyruvate intolerance; and lowered hepatic insulin action. Mechanistically, DHT increased hepatic androgen-receptor binding to phosphoinositide-3-kinase (PI3K)-p85, resulting in dissociation of PI3K-p85 from PI3K-p110, leading to reduced PI3K activity and decreased p-AKT and, thus, lowered insulin action. DHT increased gluconeogenesis via direct transcriptional regulation of gluconeogenic enzymes and coactivators. The hepatocyte model recapitulated the in vivo findings. The DHT-induced hepatocyte insulin resistance was reversed by the androgen-receptor antagonist, flutamide. These findings present a phenotype (i.e., impaired glucose tolerance and disrupted glucose metabolism) in a lean hyperandrogenemia model (low-dose DHT) and data to support 2 molecular mechanisms that help drive androgen-induced impaired glucose metabolism.

Androgen and its receptor (AR) play a critical role in reproductive function under both physiological and pathophysiological conditions. Female AR global knockout mice are subfertile due to both neuroendocrine and ovarian defects. Female offspring from prenatally androgenized heterozygous AR pregnant mice showed rescued estrous cyclicity and fertility. Ar is expressed in granulosa cells, theca interstitial cells, and oocytes in the ovary. We created mice with theca-specific deletion of Ar (ThARKO) by crossing Cyp17-iCre mice that express Cre recombinase under cytochrome P450 17A1 (Cyp17) promoter with Arfl/fl mice. ThARKO mice exhibited no significant differences in pubertal onset or fertility compared with control littermates, and neither estrogen or testosterone levels were different between these groups. Therefore, Ar expression in theca cells likely does not influence fertility nor androgen levels in female mice. We then tested the role of AR in theca cells under hyperandrogenemic condition. After treatment with a pathophysiological level of dihydrotestosterone (DHT), control mice (control-DHT) showed acyclicity and infertility. However, estrous cycles and fertility were altered to a significantly less degree in ThARKO-DHT mice than in control-DHT mice. Messenger RNA (mRNA) levels of Lhcgr (luteinizing hormone receptor) and Timp1 (tissue inhibitor of metalloproteinase 1, and inhibitor of matrix metalloproteinase) were significantly lower in control-DHT ovary compared with control-no DHT ovaries, whereas mRNA levels of Fshr (follicle-stimulating hormone receptor) were significantly higher. Timp1 gene expression was comparable in the ThARKO-DHT and the control-no DHT ovary. We speculate that the preserved level of Timp1 in ThARKO-DHT mice contributes to retained reproductive function.

There are reports that ataxia telangiectasia mutated (ATM) plays a role in insulin-stimulated Akt phosphorylation, although this is not the case in some cell types. Because Akt plays a key role in insulin signaling, which leads to glucose transport in skeletal muscle, the predominant tissue in insulin-stimulated glucose disposal, we examined whether insulin-stimulated Akt phosphorylation and (or) glucose transport would be decreased in skeletal muscle of mice lacking functional ATM, compared with muscle from wild-type mice. We found that in vitro insulin-stimulated Akt phosphorylation was normal in soleus muscle from mice with 1 nonfunctional allele of ATM (ATM+/−) and from mice with 2 nonfunctional alleles (ATM−/−). However, insulin did not stimulate glucose transport or the phosphorylation of AS160 in ATM−/− soleus. ATM protein level was markedly higher in wild-type extensor digitorum longus (EDL) than in wild-type soleus. In EDL from ATM−/− mice, insulin did not stimulate glucose transport. However, in contrast to findings for soleus, insulin-stimulated Akt phosphorylation was blunted in ATM−/− EDL, concomitant with a tendency for insulin-stimulated phosphatidylinositol 3-kinase activity to be decreased. Together, the findings suggest that ATM plays a role in insulin-stimulated glucose transport at the level of AS160 in muscle comprised of slow and fast oxidative-glycolytic fibers (soleus) and at the level of Akt in muscle containing fast glycolytic fibers (EDL).

Objective The glucose and dehydroascorbic acid (DHA) transporter GLUT1 contains a phosphorylation site, S490, for ataxia telangiectasia mutated (ATM). The objective of this study was to determine whether ATM and GLUT1-S490 regulate GLUT1. Research Design and Methods L6 myoblasts and mouse skeletal muscles were used to study the effects of ATM inhibition, ATM activation, and S490 mutation on GLUT1 localization, trafficking, and transport activity. Results In myoblasts, inhibition of ATM significantly diminished cell surface GLUT1, glucose and DHA transport, GLUT1 externalization, and association of GLUT1 with Gα-interacting protein-interacting protein, C-terminus (GIPC1), which has been implicated in recycling of endosomal proteins. In contrast, ATM activation by doxorubicin (DXR) increased DHA transport, cell surface GLUT1, and the GLUT1/GIPC1 association. S490A mutation decreased glucose and DHA transport, cell surface GLUT1, and interaction of GLUT1 with GIPC1, while S490D mutation increased transport, cell surface GLUT1, and the GLUT1/GIPC1 interaction. ATM dysfunction or ATM inhibition reduced DHA transport in extensor digitorum longus (EDL) muscles and decreased glucose transport in EDL and soleus. In contrast, DXR increased DHA transport in EDL. Conclusions These results provide evidence that ATM and GLUT1-S490 promote cell surface GLUT1 and GLUT1-mediated transport in skeletal muscle associated with upregulation of the GLUT1/GIPC1 interaction.