PFOS Impairs Mitochondrial Biogenesis and Dynamics and Reduces Oxygen Consumption in Human Trophoblasts.

Perfluorooctane sulfonate (PFOS), a synthetic chemical used in various commercial applications and industrial settings, has led to contamination of drinking water and has been detected in the bloodstream of pregnant women with gestational complications. Recent investigations have indicated that PFOS disrupts placental function; however, the mechanism remains elusive. Given the significant abundance of mitochondria in the placenta, which play a pivotal role in fulfilling the heightened energy requirements of pregnancy, our research aimed to examine the repercussions of PFOS exposure on mitochondrial dynamics within placental trophoblasts. Specifically, human trophoblasts (HTR-8/SVneo) were exposed to environmentally relevant concentrations of PFOS ranging from 0.1 to 50 µM for 48 hours. Findings revealed that PFOS exposure elicited a concentration-dependent decrease in basal, maximal, and ATP-linked respiration. PFOS inhibited the activity of electron transport complexes I, II, and III, resulting in diminished ATP production. Furthermore, PFOS reduced mitochondrial DNA copy number, indicating less mitochondrial content. Concurrently, there was a downregulation in the expression of mitochondrial biogenesis-related genes, including PGC-1α, NRF1, and NRF2. Notably, PFOS perturbed mitochondrial dynamics by suppressing the expression of fission-related genes (FIS1 and DRP1) and fusion-related genes (MFN1 and MFN2). In summary, our findings suggest that PFOS exposure leads to a decline in mitochondrial content and compromises the bioenergetic capacity of trophoblasts by impairing cellular respiration. This reduction in mitochondrial biogenesis and alterations in fission/fusion dynamics induced by PFOS may contribute to mitochondrial dysfunction in trophoblasts. Consequently, strategies that preserve mitochondrial function in trophoblasts may mitigate PFOS-induced impairment of placental energy metabolism.

Low Protein Programming Causes Increased Mitochondrial Fusion and Decreased Oxygen Consumption in the Hepatocytes of Female Rats.

The liver is one of the major organs involved in the regulation of glucose and lipid homeostasis. The effectiveness of metabolic activity in hepatocytes is determined by the quality and quantity of its mitochondria. Mitochondrial function is complex, and they act via various dynamic networks, which rapidly adapt to changes in the cellular milieu. Our present study aims to investigate the effects of low protein programming on the structure and function of mitochondria in the hepatocytes of adult females. Pregnant rats were fed with a control or isocaloric low-protein diet from gestational day 4 until delivery. A normal laboratory chow was given to all dams after delivery and to pups after weaning. The rats were euthanized at 4 months of age and the livers were collected from female offspring for investigating the mitochondrial structure, mtDNA copy number, mRNA, and proteins expression of genes associated with mitochondrial function. Primary hepatocytes were isolated and used for the analysis of the mitochondrial bioenergetics profiles. The mitochondrial ultrastructure showed that the in utero low-protein diet exposure led to increased mitochondrial fusion. Accordingly, there was an increase in the mRNA and protein levels of the mitochondrial fusion gene Opa1 and mitochondrial biogenesis genes Pgc1a and Essra, but Fis1, a fission gene, was downregulated. Low protein programming also impaired the mitochondrial function of the hepatocytes with a decrease in basal respiration ATP-linked respiration and proton leak. In summary, the present study suggests that the hepatic mitochondrial dysfunction induced by an in utero low protein diet might be a potential mechanism linking glucose intolerance and insulin resistance in adult offspring.

Evaluation of Hepatic Glucose Production in a Polycystic Ovary Syndrome Mouse Model.

Polycystic ovary syndrome (PCOS) is a common disease that results in disorders of glucose metabolism, such as insulin resistance and glucose intolerance. Dysregulated glucose metabolism is an important manifestation of the disease and is the key to its pathogenesis. Therefore, studies involving evaluation of glucose metabolism in PCOS are of utmost importance. Very few studies have quantified hepatic glucose production directly in PCOS models using non-radioactive glucose tracers. In this study, we discuss step-by-step instructions for the quantification of the rate of hepatic glucose production in a PCOS mouse model by measuring M+2 enrichment of [6,6-2H2]glucose, a stable isotopic glucose tracer, via gas chromatography - mass spectrometry (GCMS). This procedure involves creation of stable isotopic glucose tracer solution, use of tail vein catheter placement and infusion of the glucose tracer in both fasting and glucose-rich states in the same mouse in tandem. The enrichment of [6,6-2H2]glucose is measured using pentaacetate derivative in GCMS. This technique can be applied to a wide variety of studies involving direct measurement of the rate of hepatic glucose production.

Prenatal Low-Protein Diet Affects Mitochondrial Structure and Function in the Skeletal Muscle of Adult Female Offspring.

Gestational low-protein (LP) diet leads to glucose intolerance and insulin resistance in adult offspring. We had earlier demonstrated that LP programming affects glucose disposal in females. Mitochondrial health is crucial for normal glucose metabolism in skeletal muscle. In this study, we sought to analyze mitochondrial structure, function, and associated genes in skeletal muscles to explore the molecular mechanism of insulin resistance LP-programmed female offspring. On day four of pregnancy, rats were assigned to a control diet containing 20% protein or an isocaloric 6% protein-containing diet. Standard laboratory diet was given to the dams after delivery until the end of weaning and to pups after weaning. Gestational LP diet led to changes in mitochondrial ultrastructure in the gastrocnemius muscles, including a nine-fold increase in the presence of giant mitochondria along with unevenly formed cristae. Further, functional analysis showed that LP programming caused impaired mitochondrial functions. Although the mitochondrial copy number did not show significant changes, key genes involved in mitochondrial structure and function such as Fis1, Opa1, Mfn2, Nrf1, Nrf2, Pgc1b, Cox4b, Esrra, and Vdac were dysregulated. Our study shows that prenatal LP programming induced disruption in mitochondrial ultrastructure and function in the skeletal muscle of female offspring.

Pathology of hyperandrogenemia in the oocyte of polycystic ovary syndrome.

Polycystic ovary syndrome (PCOS) is the most common ovulatory disorder in the world and is associated with multiple adverse outcomes. The phenotype is widely varied, with several pathologies contributing to the spectrum of the disease including insulin resistance, obesity and hyperandrogenemia. Of these, the role of hyperandrogenemia and the mechanism by which it causes dysfunction remains poorly understood. Early studies have shown that androgens may affect the metabolic pathways of a cell, and this may pose hazards at the level of the mitochondria. As mitochondria are strictly maternally inherited, this would provide an exciting explanation not only to the pathophysiology of PCOS as a disease, but also to the inheritance pattern. This review seeks to summarize what is known about PCOS and associated adverse outcomes with focus on the role of hyperandrogenemia and specific emphasis on the oocyte.

Hyperandrogenemia alters mitochondrial structure and function in the oocytes of obese mouse with polycystic ovary syndrome.

CAPSULE: Hyperandrogenemia in an obese PCOS mouse model results in altered glucose/insulin metabolism and mitochondrial structure and function in the oocytes, in part explaining adverse outcomes and inheritance patterns seen in PCOS. OBJECTIVE: To study the oocyte quality by means of mitochondrial structure and function in a well-established classic PCOS mouse model. DESIGN: Animal study using an obese PCOS mouse model compared with control. SETTING: Animal research facility in a tertiary care university hospital setting. ANIMALS: C57/B6J mice. INTERVENTION: Three week old mice had subdermal implants of DHT controlled release pellet or placebo for 90 days. MAIN OUTCOME MEASURES: The mouse model was validated by performing glucose tolerance test, HbA1c levels, body weight and estrous cycle analyses. Oocytes were subsequently isolated and were used to investigate mitochondrial membrane potential, oxidative stress, lipid peroxidation, ATP production, mtDNA copy number, transcript abundance, histology and electron microscopy. RESULTS: Results showed glucose intolerance and hyperinsulinemia along with dysregulated estrus cycle. Analysis of the oocytes demonstrated impaired inner mitochondrial membrane function, increased ATP production and mtDNA copy number, altered RNA transcript abundance and aberrant ovarian histology. Electron microscopy of the oocytes showed severely impaired mitochondrial ultrastructure. CONCLUSION: The obese PCOS mouse model shows a decreased oocyte quality related to impaired mitochondrial function.

Polycystic Ovary Syndrome and the Forgotten Uterus.

Polycystic ovary syndrome (PCOS) is a common disorder that affects various facets of fertility. Although the ovarian and metabolic aspects of the disease is well studied, its role in uterine dysfunction is not well understood. Our objective was to review the features of endometrial and uterine aberrations in women with PCOS. A systematic literature search was performed in PubMed, Medline, and the Cochrane Library databases for papers published in English up to March 2020. The following key words were used for the search: polycystic ovary syndrome, poly cystic ovarian disease, polycystic ovaries, PCOS, PCOD, PCO, PCOM, oligoovulation, anovulation, oligomenorrhea, amenorrhea, hyperandrogenism and this was combined with terms; endometrium, infertility, uterus, progesterone resistance, endometrial hyperplasia, pregnancy outcomes, preterm delivery. In this review, we highlight various uterine pathologies that are associated with PCOS and explore its impact on fertility. We also discuss key uterine molecular pathways that are altered in PCOS that may be related to infertility, endometrial hyperplasia and cancer.

In utero low-protein-diet-programmed type 2 diabetes in adult offspring is mediated by sex hormones in rats†.

Sex steroids regulate insulin sensitivity and glucose metabolism. We had characterized a lean type 2 diabetes (T2D) rat model using gestational low-protein (LP) diet programming. Our objective was to identify if endocrine dysfunction leading to decreased sex hormone levels will precede the development of T2D and if steroid replacement will prevent the onset of the disease. Pregnant rats were fed control or isocaloric LP diet from gestational day 4 until delivery. Normal diet was given to all mothers after delivery and to pups after weaning. LP offspring developed glucose intolerance and insulin resistance at 4 months. We measured sex steroid hormone profiles and expression of key genes involved in steroidogenesis in testis and ovary. Furthermore, one-month old rats were implanted with 90-day slow release T and E2 pellets for males and females, respectively. Glucose tolerance test (GTT) and euglycemic hyperinsulinemic clamp was performed at 4 months. LP-programmed T2D males had low T levels and females had low E2 levels due to dysregulated gene expression during steroidogenesis in gonads. GTT and euglycemic hyperinsulinemic clamp showed that LP males and females were glucose intolerant and insulin resistant; however, steroid supplementation prevented the onset of glucose intolerance and insulin resistance. Rats that developed T2D by LP programming have compromised gonadal steroidogenesis leading to low T and E2 in males and females, respectively. Sex steroid supplementation prevented the onset of glucose intolerance and insulin resistance indicating low sex steroid levels could cause compromised glucose metabolism ultimately leading to T2D.

Testosterone Decreases Placental Mitochondrial Content and Cellular Bioenergetics.

Placental mitochondrial dysfunction plays a central role in the pathogenesis of preeclampsia. Since preeclampsia is a hyperandrogenic state, we hypothesized that elevated maternal testosterone levels induce damage to placental mitochondria and decrease bioenergetic profiles. To test this hypothesis, pregnant Sprague-Dawley rats were injected with vehicle or testosterone propionate (0.5 mg/kg/day) from gestation day (GD) 15 to 19. On GD20, the placentas were isolated to assess mitochondrial structure, copy number, ATP/ADP ratio, and biogenesis (Pgc-1α and Nrf1). In addition, in vitro cultures of human trophoblasts (HTR-8/SVneo) were treated with dihydrotestosterone (0.3, 1.0, and 3.0 nM), and bioenergetic profiles using seahorse analyzer were assessed. Testosterone exposure in pregnant rats led to a 2-fold increase in plasma testosterone levels with an associated decrease in placental and fetal weights compared with controls. Elevated maternal testosterone levels induced structural damage to the placental mitochondria and decreased mitochondrial copy number. The ATP/ADP ratio was reduced with a parallel decrease in the mRNA and protein expression of Pgc-1α and Nrf1 in the placenta of testosterone-treated rats compared with controls. In cultured trophoblasts, dihydrotestosterone decreased the mitochondrial copy number and reduced PGC-1α, NRF1 mRNA, and protein levels without altering the expression of mitochondrial fission/fusion genes. Dihydrotestosterone exposure induced significant mitochondrial energy deficits with a dose-dependent decrease in basal respiration, ATP-linked respiration, maximal respiration, and spare respiratory capacity. In summary, our study suggests that the placental mitochondrial dysfunction induced by elevated maternal testosterone might be a potential mechanism linking preeclampsia to feto-placental growth restriction.

Prenatal androgen induced lean PCOS impairs mitochondria and mRNA profiles in oocytes.

Polycystic ovary syndrome (PCOS) is the most common ovulatory defect in women. Although most PCOS patients are obese, a subset of PCOS women are lean but show similar risks for adverse fertility outcomes. A lean PCOS mouse model was created using prenatal androgen administration. This developmentally programmed mouse model was used for this study. Our objective was to investigate if mitochondrial structure and functions were compromised in oocytes obtained from lean PCOS mouse. The lean PCOS mouse model was validated by performing glucose tolerance test, HbA1c levels, body weight and estrous cycle analyses. Oocytes were isolated and were used to investigate inner mitochondrial membrane potential, oxidative stress, lipid peroxidation, ATP production, mtDNA copy number, transcript abundance, histology and electron microscopy. Our results demonstrate that lean PCOS mice has similar weight to that of the controls but exhibited glucose intolerance and hyperinsulinemia along with dysregulated estrus cycle. Analysis of their oocytes show impaired inner mitochondrial membrane function, elevated reactive oxygen species (ROS), increased RNA transcript abundance and aberrant ovarian histology. Electron microscopy of the oocytes showed impaired mitochondrial ultrastructure. In conclusion, the lean PCOS mouse model shows a decreased oocyte quality related to impaired mitochondrial ultrastructure and function.

Sex Dependent Dysregulation of Hepatic Glucose Production in Lean Type 2 Diabetic Rats.

We have characterized a lean type 2 diabetic rat model by gestational low protein programming. We aimed to identify if the regulation of hepatic glucose production (HGP) via gluconeogenesis and glycogenolysis is affected and if there are any sex differences. Fasting (6-7 months old) type 2 diabetic rats received 2H2O followed by a primed constant rate infusion of [6,6-2H2] glucose. Blood samples were drawn during steady states after 4 h of fasting and following a euglycemic hyperinsulinemic clamp. HGP and the fraction of glucose derived from gluconeogenesis under fasting and euglycemic states were measured from steady state glucose enrichments after the infusion of [6,6-2H2]glucose and 2H2O tracers. Glycogenolysis was determined by calculating the difference between total HGP and gluconeogenesis rates. Hepatic gene expression of enzymes involved in HGP were quantified using qPCR. HGP rates was similar during fasting in both groups and sexes. However, under simulated fed condition, HGP rate was suppressed in controls but not in type 2 diabetic rats. They also showed inefficient HGP suppression in a simulated fed state. Differential analysis showed that suppression of both gluconeogenesis and glycogenolysis under simulated fed state was affected in these low protein programmed type 2 diabetic rats. These effects were greater in females when compared to males. Further, key genes involved in these processes like G6Pase, Pepck, pyruvate carboxylase, and glycogen phosphorylase in liver were dysregulated. Our data shows impaired suppression of HGP via gluconeogenesis and glycogenolysis in type 2 diabetic rats with greater effects on females.

Preovulatory exposure to a protein-restricted diet disrupts amino acid kinetics and alters mitochondrial structure and function in the rat oocyte and is partially rescued by folic acid.

BACKGROUND: Detrimental exposures during pregnancy have been implicated in programming offspring to develop permanent changes in physiology and metabolism, increasing the risk for developing diseases in adulthood such as hypertension, diabetes, heart disease and obesity. This study investigated the effects of protein restriction on the metabolism of amino acids within the oocyte, liver, and whole organism in a rat model as well as effects on mitochondrial ultrastructure and function in the cumulus oocyte complex. METHODS: Wistar outbred female rats 8-11 weeks of age (n = 24) were assigned to three isocaloric dietary groups, including control (C), low protein (LP) and low protein supplemented with folate (LPF). Animals were superovulated and 48 h later underwent central catheterization. Isotopic tracers of 1-13C-5C2H3-methionine, 2H2-cysteine, U-13C3-cysteine and U-13C3-serine were administered by a 4 h prime-constant rate infusion. After sacrifice, oocytes were denuded of cumulus cells and liver specimens were obtained. RESULTS: Oocytes demonstrated reduced serine flux in LP vs. LPF (p < 0.05), reduced cysteine flux in LP and LPF vs. C (p < 0.05), and a trend toward reduced transsulfuration in LP vs. C and LPF. Folic acid supplementation reversed observed effects on serine flux and transsulfuration. Preovulatory protein restriction increased whole-body methionine transmethylation, methionine transsulfuration and the flux of serine in LP and LPF vs. C (p = 0.003, p = 0.002, p = 0.005). The concentration of glutathione was increased in erythrocytes and liver in LP and LPF vs. C (p = 0.003 and p = 0.0003). Oocyte mitochondrial ultrastructure in LP and LPF had increased proportions of abnormal mitochondria vs. C (p < 0.01 and p < 0.05). Cumulus cell mitochondrial ultrastructure in LP and LPF groups had increased proportions of abnormal mitochondria vs. C (p < 0.001 and p < 0.05). Preovulatory protein restriction altered oocyte expression of Drp1, Opa-1, Mfn1/2, Parl and Ndufb6 (p < 0.05) and Hk2 (p < 0.01), which are genes involved in mitochondrial fission (division) and fusion, mitochondrial apoptotic mechanisms, respiratory electron transport and glucose metabolism. CONCLUSIONS: Preovulatory protein restriction resulted in altered amino acid metabolism, abnormal cumulus oocyte complex mitochondrial ultrastructure and differential oocyte expression of genes related to mitochondrial biogenesis.

Folate treatment partially reverses gestational low-protein diet-induced glucose intolerance and the magnitude of reversal is age and sex dependent.

OBJECTIVES: Gestational low-protein (LP) programming causes glucose intolerance (GI) and insulin resistance (IR) in adult offspring. Folate supplementation has been shown to rescue the offspring from various programming effects. The aim of this study was to investigate whether folate supplementation during pregnancy reverses LP-induced GI and IR. METHODS: Pregnant rats were fed control (20% protein), isocaloric low-protein (LP, 6%) or LP with 5 mg/kg folate (LPF) diets from gestational day 4 to delivery. The control diet was given during lactation and to pups after weaning. Glucose tolerance test was done at 1, 2, and 3 mo of age followed by euglycemic-hyperinsulinemic clamp at 4 mo. Rats were sacrificed at 4 mo and their gonadal, renal, inguinal, brown fat, and pancreas were weighed and expressed relative to their body weight. RESULTS: LP- and LPF-fed dams showed similar weight loss during late pregnancy after decreased feed intake. Both LP and LPF pups were smaller at birth but their weights caught up like that of controls by 3 mo. In males, folate supplementation reduced LP-induced GI at 2 mo (glucose area under the curve [AUC]: 1940 mmol/L × 180 min in LP, 1629 mmol/L × 180 min in LPF, and 1653 mmol/L × 180 min in controls; P <0.05, LP versus control and P <0.01, LP versus LPF) but the effect diminished at 3 mo. In females, folate reduced GI at 1 mo (glucose AUC: 1406 mmol/L × 180 min in LP, 1264 mmol/L × 180 min in LPF, and 1281 mmol/L × 180 min in controls; P <0.05, LP versus control and LP versus LPF) but had no effect at 2 and 3 mo. Interestingly, the LPF group had higher pancreatic weights than other groups, suggesting that folate helps in pancreatic development enabling the LPF rats to produce/secrete more insulin to maintain euglycemia. Euglycemic-hyperinsulinemic clamp shows both LP and LPF are insulin resistant compared with controls by 4 mo with LPF more severe than LP in males. Interestingly, females were more insulin resistant than males. CONCLUSIONS: Folate treatment partially reverses LP-induced GI and the magnitude of reversal is age and sex dependent. Furthermore, folate treatment does not reverse IR in either sex but makes it worse in males at 4 mo. The present study demonstrated that folate treatment is not sufficient to rescue the LP programming effects.

Gestational Protein Restriction Impairs Glucose Disposal in the Gastrocnemius Muscles of Female Rats.

Gestational low-protein (LP) diet causes hyperglycemia and insulin resistance in adult offspring, but the mechanism is not clearly understood. In this study, we explored the role of insulin signaling in gastrocnemius muscles of gestational LP-exposed female offspring. Pregnant rats were fed a control (20% protein) or an isocaloric LP (6%) diet from gestational day 4 until delivery. Normal diet was given to mothers after delivery and to pups after weaning until necropsy. Offspring were euthanized at 4 months, and gastrocnemius muscles were treated with insulin ex vivo for 30 minutes. Messenger RNA and protein levels of molecules involved in insulin signaling were assessed at 4 months. LP females were smaller at birth but showed rapid catchup growth by 4 weeks. Glucose tolerance test in LP offspring at 3 months showed elevated serum glucose levels (P < 0.01; glycemia Δ area under the curve 342 ± 28 in LP vs 155 ± 23 in controls, mmol/L * 120 minutes) without any change in insulin levels. In gastrocnemius muscles, LP rats showed reduced tyrosine phosphorylation of insulin receptor substrate 1 upon insulin stimulation due to the overexpression of tyrosine phosphatase SHP-2, but serine phosphorylation was unaffected. Furthermore, insulin-induced phosphorylation of Akt, glycogen synthase kinase (GSK)-3α, and GSK-3ß was diminished in LP rats, and they displayed an increased basal phosphorylation (inactive form) of glycogen synthase. Our study shows that gestational protein restriction causes peripheral insulin resistance by a series of phosphorylation defects in skeletal muscle in a mechanism involving insulin receptor substrate 1, SHP-2, Akt, GSK-3, and glycogen synthase causing dysfunctional GSK-3 signaling and increased stored glycogen, leading to distorted glucose homeostasis.

Novel lean type 2 diabetic rat model using gestational low-protein programming.

BACKGROUND: Type 2 diabetes (T2D) in lean individuals is not well studied and up to 26% of diabetes occurs in these individuals. Although the cause is not well understood, it has been primarily attributed to nutritional issues during early development. OBJECTIVE: Our objective was to develop a lean T2D model using gestational low-protein (LP) programming. STUDY DESIGN: Pregnant rats were fed control (20% protein) or isocaloric LP (6%) diet from gestational day 4 until delivery. Standard diet was given to dams after delivery and to pups after weaning. Glucose tolerance test was done at 2, 4, and 6 months of age. Magnetic resonance imaging of body fat for females was done at 4 months. Rats were sacrificed at 4 and 8 months of age and their perigonadal, perirenal, inguinal, and brown fat were weighed and expressed relative to their body weight. Euglycemic-hyperinsulinemic clamp was done around 6 months of age. RESULTS: Male and female offspring exposed to a LP diet during gestation developed glucose intolerance and insulin resistance (IR). Further, glucose intolerance progressed with increasing age and occurred earlier and was more severe in females when compared to males. Euglycemic-hyperinsulinemic clamp showed whole body IR in both sexes, with females demonstrating increased IR compared to males. LP females showed a 4.5-fold increase in IR while males showed a 2.5-fold increase when compared to their respective controls. Data from magnetic resonance imaging on female offspring showed no difference in the subcutaneous, inguinal, and visceral fat content. We were able to validate this observation by sacrificing the rats at 4 and 8 months and measuring total body fat content. This showed no differences in body fat content between control and LP offspring in either males or females. Additionally, diabetic rats had a similar body mass index to that of the controls. CONCLUSION: LP gestational programming produces a progressively worsening T2D model in rats with a lean phenotype without obesity.

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.

Adrenomedullin2 (ADM2)/intermedin (IMD) in rat ovary: changes in estrous cycle and pregnancy and its role in ovulation and steroidogenesis.

Adrenomedullin2 (ADM2) is reported to facilitate embryo implantation and placental development. Therefore, the current study was undertaken to identify if ADM2 has a functional role in ovary to facilitate its reproductive actions. This study shows that the expression of ADM2 is differentially regulated in rat estrous cycle and that ADM2 increases the synthesis and secretion of 17beta-estradiol accompanied with an increase in the expression of steroidogenic factor 1 (Sf1), estrogen receptor Esr1, and enzymes involved in steroidogenesis in equine chorionic gonadotropin (eCG)-treated rat ovaries. In addition, inhibition of endogenous ADM2 function in eCG-treated immature rats caused impaired ovulation. Furthermore, the mRNA expression of Adm2 and receptor activity modifying protein 3 is higher in the ovary on Day 18 compared to nonpregnant and pregnant rats on Day 22. ADM2-like immunoreactivity is localized in granulosa cells, blood vessels, oocytes, cumulous oophorus, and corpus luteum of pregnant ovaries, suggesting a potential role for ADM2 in the ovary. This is supported by the presence of ADM2-like immunoreactivity in the corpus luteum during pregnancy and a decline in aromatase immunoreactivity in corpus luteum on Day 9 of gestation in rats infused with ADM2 antagonist during implantation and decidualization phase. Taken together, this study suggests a potential involvement of ADM2 in the rat ovary in regulating synthesis of estradiol to support ovulation and facilitate efficient implantation and placental development for a successful pregnancy.