Hemin restores ACTH-induced glucocorticoid response in insulin-resistant rats.

The sustained consumption of sucrose-rich diet has deleterious effects on the adrenal cortex, impairing its steroidogenic capacity. As hemin treatment has been shown to exert cytoprotective effects (e.g.

Exploring the impact of caloric restriction on molecular mechanisms of liver damage induced by sucrose intake in the drinking water.

A positive association has been demonstrated between consumption of sucrose-sweetened beverages and the prevalence of metabolic dysfunction-associated steatotic liver disease (MASLD). Since the administration of 30 % sucrose in the drinking water (sucrose-rich diet (SRD)) to rats has proven to be a good model of systemic insulin resistance, the aim of our study was to analyse the effect of caloric restriction applied on SRD-treated rats by switching back to a standard diet, on liver morphology, function and metabolism. Consumption of an SRD causes a metabolic shift towards gluconeogenesis and fatty acid synthesis leading to an increase in TAG levels in plasma and in the liver that were associated with a decrease in insulin sensitivity.

Functional Autoreactive Anti-β2 Adrenergic Antibodies May Contribute to Insulin Resistance Profile in Patients with Chronic Chagas Disease.

Potential activation of β2 adrenergic receptors (β2AR) by specific autoreactive antibodies (Abs) that arise during the host reaction to , could contribute to the elevated prevalence of metabolic disturbances described in patients with chronic Chagas disease (CCD). This study aimed to determine the prevalence of anti-β2AR Abs in patients with CCD, as well as the correlation of these Abs with the presence of glucose and lipid metabolism disturbances, in order to explore their association with an insulin resistance profile. Additionally, we tested the functional effects of anti-β2AR Abs employing an in vitro bioassay with neuroendocrine cells expressing β2AR.

KSHV G-protein coupled receptor vGPCR oncogenic signaling upregulation of Cyclooxygenase-2 expression mediates angiogenesis and tumorigenesis in Kaposi's sarcoma.

Kaposi's sarcoma-associated herpesvirus (KSHV) vGPCR is a constitutively active G protein-coupled receptor that subverts proliferative and inflammatory signaling pathways to induce cell transformation in Kaposi's sarcoma. Cyclooxygenase-2 (COX-2) is an inflammatory mediator that plays a key regulatory role in the activation of tumor angiogenesis. Using two different transformed mouse models and tumorigenic full KSHV genome-bearing cells, including KSHV-Bac16 based mutant system with a vGPCR deletion, we demostrate that vGPCR upregulates COX-2 expression and activity, signaling through selective MAPK cascades.

The enrichment of maternal environment prevents pre-term birth in a mice model.

Maternal lifestyle affects both mother health and pregnancy outcome in humans. Several studies have demonstrated that interventions oriented toward reducing stress and anxiety have positive effects on pregnancy complications such as preeclampsia, excessive gestational weight, gestational diabetes and preterm birth. In this work, we showed that the environmental enrichment (EE), defined as a noninvasive and biologically significant stimulus of the sensory pathway combined with voluntary physical activity, prevented preterm birth (PTB) rate by 40% in an inflammatory mouse model induced by the systemic administration of bacterial lipopolysaccharide (LPS).

Melatonin prevents early pituitary dysfunction induced by sucrose-rich diets.

While physiological levels of glucocorticoids are required to ensure proper functions of the body, consistently high levels may engender several deleterious consequences. We have previously shown an increase in the activity of the hypothalamic-pituitary-adrenal (HPA) axis in rats fed sucrose-rich diets (SRD). The main goal of this study was to analyze the processes involved in the modulation of the pituitary production of ACTH by SRD, and to test melatonin as a possible therapeutic agent for the prevention of the HPA axis dysfunction.

Impaired HPA axis function in diabetes involves adrenal apoptosis and phagocytosis.

Purpose: The aim of the present study was to analyze the involvement of oxidative stress and inflammation in the modulation of glucocorticoid production in the adrenal cortex of diabetic rats.

Methods: Male Wistar rats were treated with or without streptozotocin (STZ, an insulinopenic model of diabetes) and either α-lipoic (90 mg/kg ip.), α-tocopherol (200 mg/kg po.

A role for the endocannabinoid system in premature luteal regression and progesterone withdrawal in lipopolysaccharide-induced early pregnancy loss model.

Study Question: What is the role of the endocannabinoid system (eCS) in the alterations of the endocrine system in a murine model of lipopolysaccharide (LPS)-induced miscarriage?

Summary Answer: In 7-days pregnant wild type, but not cannabinoid receptor type 1 knockout (CB1-KO) mice, LPS increased COX-2 expression and prostaglandin F (PGF) production in the uterus leading to lower expression of prolactin receptor in the ovary and a marked regression of corpora lutea (CL), suggesting that the eCS mediates the deleterious effects of LPS on reproductive events.

What Is Known Already: Appropriate systemic progesterone levels are critical for a successful pregnancy outcome. Precocious loss of luteal progesterone (P4) secretion leads to miscarriage in rodents.

Moderate Exercise Prevents Functional Remodeling of the Anterior Pituitary Gland in Diet-Induced Insulin Resistance in Rats: Role of Oxidative Stress and Autophagy.

A sustained elevation of glucocorticoid production, associated with the establishment of insulin resistance (IR) could add to the deleterious effects of the IR state. The aim of this study is to analyze the consequences of long-term feeding with a sucrose-rich diet (SRD) on Pomc/ACTH production, define the underlying cellular processes, and determine the effects of moderate exercise (ME) on these parameters. Animals fed a standard chow with or without 30% sucrose in the drinking water were subjected to ME.

Lipopolysaccharide-induced murine embryonic resorption involves changes in endocannabinoid profiling and alters progesterone secretion and inflammatory response by a CB1-mediated fashion.

Genital tract infections are a common complication of human pregnancy that can result in miscarriage. We have previously shown that a lipopolysaccharide (LPS) induces embryonic resorption in a murine model of inflammatory miscarriage. This is accompanied by a dramatic decrease in systemic progesterone levels associated with a robust pro-inflammatory response that results in embryo resorption.

Crosstalk between nitric oxide synthases and cyclooxygenase 2 in the adrenal cortex of rats under lipopolysaccharide treatment.

The effect of lipopolysaccharide on the modulation of steroid production by adrenal cells has been recently acknowledged. The purpose of this study was to determine the in vivo effects of LPS on adrenal cyclooxygenase 2 (COX-2) expression, analyze its crosstalk with the nitric oxide synthase (NOS) system, and assess its involvement on the modulation of glucocorticoid production. Male Wistar rats were injected with LPS and with specific inhibitors for NOS and COX activities.

Insulin sensitization with a peroxisome proliferator-activated receptor γ agonist prevents adrenocortical lipid infiltration and secretory changes induced by a high-sucrose diet.

It has been hypothesized that deviations in glucocorticoid secretion and/or action may contribute to somatic and biochemical changes observed in patients with and animal models of insulin resistance (IR). In this study, we analyzed changes in rat adrenocortical function and morphology associated with the development of IR, generated in male adult rats by the addition of 30% sucrose to the drinking water. Caloric intake, body and adipose tissue weights, and biochemical parameters associated with IR were determined.

Effects of GABAB receptor agonists and antagonists on glycemia regulation in mice.

γ-Aminobutyric acid (GABA) inhibits insulin secretion through GABA(B) receptors in pancreatic β-cells. We investigated whether GABA(B) receptors participated in the regulation of glucose homeostasis in vivo. BALB/c mice acutely pre-injected with the GABA(B) receptor agonist baclofen (7.

Effects of heme oxygenase isozymes on Leydig cells steroidogenesis.

In the present study, we demonstrate the expression of heme oxygenase (HO) isozymes, HO-1 and HO-2 (listed as HMOX1 and HMOX2 in the MGI Database), in MA-10 Leydig tumor cells and its effect on steroidogenesis. The well-known HO inducer, hemin, increased both HO-1 and HO-2 protein levels and HO-specific activity. Induction of HO by hemin inhibited basal, hCG-, and dibutyryl cAMP (db-cAMP)-induced steroidogenesis in a reversible way.

Endogenous glucocorticoids participate in retinal degeneration during continuous illumination.

Continuous illumination (CI) induces an oxidative stress of the retina which is involved in light-induced retinal degeneration (LIRD). As the increase of glucocorticoids (GC) could also collaborate in the damage, adrenalectomized (ADX) and sham-operated rats (control, CTL) were submitted to CI, and their eyes were studied at light and electron microscopic levels. After CI, ADX retinas were significantly thicker than CTL retinas.

Involvement of nitric oxide synthase in the mechanism of histamine-induced inhibition of Leydig cell steroidogenesis via histamine receptor subtypes in Sprague-Dawley rats.

This study was conducted to shed light on the so far unexplored intracellular mechanisms underlying negative modulation of Leydig cell steroidogenesis by histamine (HA). Using the MA-10 cell line and highly purified rat Leydig cells as experimental models, we examined the effect of the amine on biochemical steps known to be modulated by HA or involved in LH/hCG action. In agreement with previous findings, HA at 10 microM showed a potent inhibitory effect on hCG-stimulated steroid synthesis, regardless of the gonadotropin concentration used.

Age related changes from youth to adulthood in rat brain cortex: nitric oxide synthase and mitochondrial respiratory function.

Age related changes in brain cortex NO metabolism were investigated in mitochondria and cytosolic extracts from youth to adulthood. Decreases of 19%, 40% and 71% in NO production were observed in mitochondrial fractions from 3, 7, and 14 months old rats, respectively, as compared with 1-month-old rats. Decreased nNOS protein expression in 14 months old rats was also observed in mitochondria as compared with the nNOS protein expression in 1-month-old rats.

Effect of ocular hypertension on retinal nitridergic pathway activity.

Purpose: Understanding the mechanisms of neuronal cell death in glaucoma is important for devising new treatments. Excitatory amino acids, excessive Ca(2+) influx, and formation of nitric oxide (NO) via NO synthase (NOS)-1 could be involved in glaucomatous neuropathy. The purpose of the present study was to examine the retinal nitridergic pathway activity in rats exposed to experimentally elevated intraocular pressure.

Characterization of L-arginine transport in adrenal cells: effect of ACTH.

Nitric oxide synthesis depends on the availability of its precursor L-arginine, which could be regulated by the presence of a specific uptake system. In the present report, the characterization of the L-arginine transport system in mouse adrenal Y1 cells was performed. L-arginine transport was mediated by the cationic/neutral amino acid transport system y+L and the cationic amino acid transporter (CAT) y+ in Y1 cells.

Sequential NO production by mitochondria and endoplasmic reticulum during induced apoptosis.

Early stages of rat thymocyte apoptosis measured as annexin-V positive events and induced by methylprednisolone (MPS), etoposide, and thapsigargin, showed a sequential increase in nitric oxide (NO) production by mitochondrial and endoplasmic reticulum membranes. Thapsigargin induced the highest NO production, a sevenfold increase as compared with untreated thymocytes, in mitochondrial and microsomal membranes. MPS and etoposide were equally effective in increasing NO production by mitochondrial membranes by a factor of 4-5, with only a slight increase in NO production by endoplasmic reticulum membranes.

Photic regulation of L-arginine uptake in the golden hamster retina.

One of the limiting steps in the regulation of nitric oxide (NO) synthesis is the availability of its precursor, L-arginine, which depends on the presence of a specific uptake system. A characterization of the L-arginine uptake mechanism in the golden hamster retina was performed. This mechanism was stereospecific, saturable, and monophasic, with an apparent of 56.

Expression of nitric oxide synthases in rat adrenal zona fasciculata cells.

Nitric oxide (NO) synthase (NOS) expression was analyzed in rat adrenal zona fasciculata. Both neuronal NOS and endothelial NOS mRNAs were detected by RT-PCR, immunohistochemistry, and immunoblot analysis. The biochemical characterization of adrenal zona fasciculata NOS enzymatic activity confirmed the presence of a constitutive isoform.