Igf3 activates {beta}-catenin signaling to stimulate spermatogonial differentiation in zebrafish
We reported previously that zebrafish Fsh promoted the differentiation of type A undifferentiated spermatogonia (Aund) by stimulating the production of factors that advance germ cell differentiation, such as androgens, insulin-like peptide 3 (Insl3) and insulin-like growth factor 3 (Igf3). In addition, Fsh also modulated the transcript levels of several other genes, including some belonging to the Wnt signaling pathway. Here, we evaluated if and how Fsh utilizes part of the canonical Wnt pathway to regulate the development of spermatogonia. We quantified the proliferation activity and relative section areas occupied by Aun...
Source: Journal of Endocrinology - August 3, 2018 Category: Endocrinology Authors: Safian, D., Bogerd, J., Schulz, R. W. Tags: Research Source Type: research
Sodium butyrate supplementation ameliorates diabetic inflammation in db/db mice
Endotoxemia has been recognized to be closely accompanied with type 2 diabetes mellitus (T2DM) and is responsible for many diabetic complications. Recent study suggests the potential role of butyrate, a short-chain fatty acid (SCFA) from microbiota metabolite, on T2DM. Gut-leak is a key event in diabetic-endotoxemia. To investigate if butyrate could ameliorate diabetic-endotoxemia, both in vivo and in vitro experiments were carried out in the present study. The effect of butyrate supplementation on blood HbA1c and inflammatory cytokines were determined in db/db mice; gut barrier integrity and expression of tight junction p...
Source: Journal of Endocrinology - July 31, 2018 Category: Endocrinology Authors: Xu, Y.-H., Gao, C.-L., Guo, H.-L., Zhang, W.-Q., Huang, W., Tang, S.-S., Gan, W.-J., Xu, Y., Zhou, H., Zhu, Q. Tags: Research Source Type: research
Sex-specific changes in postnatal GH and PRL secretion in somatotrope LEPR-null mice
The developing pituitary is a rapidly changing environment that is constantly meeting the physiological demands of the growing organism. During early postnatal development, the anterior pituitary is refining patterns of anterior hormone secretion in response to numerous genetic factors. Our laboratory previously developed a somatotrope leptin receptor (LEPR) deletion mouse model that had decreased lean body mass, disrupted metabolism, decreased GH stores and was GH deficient as an adult. To understand how deletion of LEPR in somatotropes altered GH, we turned our attention to postnatal development. The current study examin...
Source: Journal of Endocrinology - July 31, 2018 Category: Endocrinology Authors: Allensworth-James, M. L., Odle, A., Haney, A., MacNicol, M., MacNicol, A., Childs, G. Tags: Research Source Type: research
cGMP-dependent protein kinase-2 regulates bone mass and prevents diabetic bone loss
NO/cGMP signaling is important for bone remodeling in response to mechanical and hormonal stimuli, but the downstream mediator(s) regulating skeletal homeostasis are incompletely defined. We generated transgenic mice expressing a partly-activated, mutant cGMP-dependent protein kinase type 2 (PKG2R242Q) under control of the osteoblast-specific Col1a1 promoter to characterize the role of PKG2 in post-natal bone formation. Primary osteoblasts from these mice showed a two- to three-fold increase in basal and total PKG2 activity; they proliferated faster and were resistant to apoptosis compared to cells from WT mice. Male Col1a...
Source: Journal of Endocrinology - July 24, 2018 Category: Endocrinology Authors: Ramdani, G., Schall, N., Kalyanaraman, H., Wahwah, N., Moheize, S., Lee, J. J., Sah, R. L., Pfeifer, A., Casteel, D. E., Pilz, R. B. Tags: Research Source Type: research
STK25 regulates oxidative capacity and metabolic efficiency in adipose tissue
Whole-body energy homeostasis at over-nutrition critically depends on how well adipose tissue remodels in response to excess calories. We recently identified serine/threonine protein kinase (STK)25 as a critical regulator of ectopic lipid storage in non-adipose tissue and systemic insulin resistance in the context of nutritional stress. Here, we investigated the role of STK25 in regulation of adipose tissue dysfunction in mice challenged with a high-fat diet. We found that overexpression of STK25 in high-fat-fed mice resulted in impaired mitochondrial function and aggravated hypertrophy, inflammatory infiltration and fibro...
Source: Journal of Endocrinology - July 24, 2018 Category: Endocrinology Authors: Sutt, S., Cansby, E., Paul, A., Amrutkar, M., Nunez-Duran, E., Kulkarni, N. M., Stahlman, M., Boren, J., Laurencikiene, J., Howell, B. W., Enerback, S., Mahlapuu, M. Tags: Research Source Type: research
Diet-induced thermogenesis: fake friend or foe?
Diet-induced thermogenesis (DIT) is energy dissipated as heat after a meal, contributing 5–15% to total daily energy expenditure (EE). There has been a long interest in the intriguing possibility that a defect in DIT predisposes to obesity. However, the evidence is conflicting; DIT is usually quantified by indirect calorimetry, which does not measure heat. Using gas exchange, indirect calorimetry measures total post-prandial EE, which comprises heat energy produced from brown adipose tissue (BAT) and energy required for processing and storing nutrients. We questioned whether DIT is reliably quantified by indirect cal...
Source: Journal of Endocrinology - July 24, 2018 Category: Endocrinology Authors: Ho, K. K. Y. Tags: Review Source Type: research
The role of kisspeptin neurons in reproduction and metabolism
Kisspeptin is a neuropeptide with a critical role in the function of the hypothalamic–pituitary–gonadal (HPG) axis. Kisspeptin is produced by two major populations of neurons located in the hypothalamus, the rostral periventricular region of the third ventricle (RP3V) and arcuate nucleus (ARC). These neurons project to and activate gonadotrophin-releasing hormone (GnRH) neurons (acting via the kisspeptin receptor, Kiss1r) in the hypothalamus and stimulate the secretion of GnRH. Gonadal sex steroids stimulate kisspeptin neurons in the RP3V, but inhibit kisspeptin neurons in the ARC, which is the underlying mecha...
Source: Journal of Endocrinology - July 24, 2018 Category: Endocrinology Authors: Harter, C. J. L., Kavanagh, G. S., Smith, J. T. Tags: Review Source Type: research
Impact of prematurity for pancreatic islet and beta-cell development
As increasing numbers of babies born preterm survive into adulthood, it is becoming clear that, in addition to the well-described risks of neurodevelopmental sequelae, there also are increased risks for non-communicable diseases, including diabetes. Epidemiological studies indicate that risks are increased even for birth at late preterm and early term gestations and for both type 1 and type 2 diabetes. Thus, factors related to preterm birth likely affect development of the fetal and neonatal beta-cell in addition to effects on peripheral insulin sensitivity. These factors could operate prior to preterm birth and be related...
Source: Journal of Endocrinology - July 24, 2018 Category: Endocrinology Authors: Bloomfield, F. H. Tags: Review Source Type: research
mTOR signaling in the arcuate nucleus of the hypothalamus mediates the anorectic action of estradiol
Current evidence suggests that estradiol (E2), the main ovarian steroid, modulates energy balance by regulating both feeding and energy expenditure at the central level, through the energy sensor AMP-activated protein kinase (AMPK). We hypothesized that the hypothalamic mechanistic target of rapamycin (mTOR) pathway, a well-established nutrient sensor and modulator of appetite and puberty, could also mediate the anorectic effect of E2. Our data showed that ovariectomy (OVX) elicited a marked downregulation of the mTOR signaling in the arcuate nucleus of the hypothalamus (ARC), an effect that was reversed by either E2 repla...
Source: Journal of Endocrinology - July 16, 2018 Category: Endocrinology Authors: Gonzalez-Garcia, I., Martinez de Morentin, P. B., Estevez-Salguero, A., Contreras, C., Romero-Pico, A., Ferno, J., Nogueiras, R., Dieguez, C., Tena-Sempere, M., Tovar, S., Lopez, M. Tags: Research Source Type: research
Transcriptional activity of oestrogen receptors in the course of embryo development
Oestrogens are well-known proliferation and differentiation factors that play an essential role in the correct development of sex-related organs and behaviour in mammals. With the use of the ERE-Luc reporter mouse model, we show herein that throughout mouse development, oestrogen receptors (ERs) are active starting from day 12 post conception. Most interestingly, we show that prenatal luciferase expression in each organ is proportionally different in relation to the germ layer of the origin. The luciferase content is highest in ectoderm-derived organs (such as brain and skin) and is lowest in endoderm-derived organs (such ...
Source: Journal of Endocrinology - July 16, 2018 Category: Endocrinology Authors: Della Torre, S., Rando, G., Meda, C., Ciana, P., Ottobrini, L., Maggi, A. Tags: Research Source Type: research
Mitochondrial oxidative stress in obesity: role of the mineralocorticoid receptor
Obesity is a multifaceted, chronic, low-grade inflammation disease characterized by excess accumulation of dysfunctional adipose tissue. It is often associated with the development of cardiovascular (CV) disorders, insulin resistance and diabetes. Under pathological conditions like in obesity, adipose tissue secretes bioactive molecules called ‘adipokines’, including cytokines, hormones and reactive oxygen species (ROS). There is evidence suggesting that oxidative stress, in particular, the ROS imbalance in adipose tissue, may be the mechanistic link between obesity and its associated CV and metabolic complicat...
Source: Journal of Endocrinology - July 16, 2018 Category: Endocrinology Authors: Lefranc, C., Friederich-Persson, M., Palacios-Ramirez, R., Nguyen Dinh Cat, A. Tags: Review Source Type: research
Biochemical and clinical aspects of glycogen storage diseases
The synthesis of glycogen represents a key pathway for the disposal of excess glucose while its degradation is crucial for providing energy during exercise and times of need. The importance of glycogen metabolism is also highlighted by human genetic disorders that are caused by mutations in the enzymes involved. In this review, we provide a basic summary on glycogen metabolism and some of the clinical aspects of the classical glycogen storage diseases. Disruptions in glycogen metabolism usually result in some level of dysfunction in the liver, muscle, heart, kidney and/or brain. Furthermore, the spectrum of symptoms observ...
Source: Journal of Endocrinology - July 16, 2018 Category: Endocrinology Authors: Ellingwood, S. S., Cheng, A. Tags: Review Source Type: research
Corticosteroids and the brain
The brain is continuously exposed to varying levels of adrenal corticosteroid hormones such as corticosterone in rodents and cortisol in humans. Natural fluctuations occur due to ultradian and circadian variations or are caused by exposure to stressful situations. Brain cells express two types of corticosteroid receptors, i.e. mineralocorticoid and glucocorticoid receptors, which differ in distribution and affinity. These receptors can mediate both rapid non-genomic and slow gene-mediated neuronal actions. As a consequence of these factors, natural (e.g. stress-induced) shifts in corticosteroid level are associated with a ...
Source: Journal of Endocrinology - July 16, 2018 Category: Endocrinology Authors: Joels, M. Tags: Review Source Type: research
Critical role for the Tsc1-mTORC1 pathway in {beta}-cell mass in Pdx1-deficient mice
Mutations in the pancreatic duodenal homeobox (PDX1) gene are associated with diabetes in humans. Pdx1-haploinsufficient mice also develop diabetes, but the molecular mechanism is unknown. To this end, we knocked down Pdx1 gene expression in mouse MIN6 insulinoma cells. Pdx1 suppression not only increased apoptotic cell death but also decreased cell proliferation, which was associated with a decrease in activity of mechanistic target of rapamycin complex 1 (mTORC1). We found that in Pdx1-deficient mice, tuberous sclerosis 1 (Tsc1) ablation in pancreatic β-cells restores β-cell mass, increases β-cell prolifer...
Source: Journal of Endocrinology - July 2, 2018 Category: Endocrinology Authors: Sun, J., Mao, L., Yang, H., Ren, D. Tags: Research Source Type: research
The delayed effects of antibiotics in type 2 diabetes, friend or foe?
An increasing amount of evidence suggests that the delayed effect of antibiotics (abx) on gut microbiota after its cessation is not as favorable as its immediate effect on host metabolism. However, it is not known how the diverse abx-dependent metabolic effects influence diabetic subjects and how gut microbiota is involved. Here, we treated db/db mice with abx cocktail for 12 days and discontinued for 24 days. We found that db/db mice showed decreased body weight and blood glucose after abx treatment, which rapidly caught up after abx cessation. Twenty-four days after abx withdrawal, db/db mice exhibit increased plasma, he...
Source: Journal of Endocrinology - July 2, 2018 Category: Endocrinology Authors: Fu, L., Qiu, Y., Shen, L., Cui, C., Wang, S., Wang, S., Xie, Y., Zhao, X., Gao, X., Ning, G., Nie, A., Gu, Y. Tags: Research Source Type: research
