We examined 5alpha-dihydrotestosterone (5alpha-DHT) inactivation and the expression of several steroid-converting enzymes with a focus on aldoketoreductases 1C (AKR1C), especially AKR1C2, in abdominal adipose tissue in men. AKR1C2 is mainly involved in the conversion of the potent androgen 5alpha-DHT to its inactive forms 5alpha-androstane-3alpha/beta,17beta-diol (3alpha/beta-diol). Subcutaneous (s.c.) and omental (Om) ...

It is widely accepted that newborn humans are provided with brown adipose tissue (BAT) and that adult humans lack, or have only a small amount, of it. Therefore the physiological role of BAT in humans is debated. It is quite clear that BAT in rodents has an important role in ...

CONTEXT: Visfatin (VF) is a recently described adipokine preferentially secreted by visceral adipose tissue (VAT) with insulin mimetic properties. OBJECTIVE: The aim of this study was to examine the association of VF with insulin sensitivity, intramyocellular lipids (IMCL), and inflammation in humans. DESIGN AND PATIENTS: VF mRNA was examined in ...

Sibutramine is a satiety-inducing serotonin-noradrenaline reuptake inhibitor that acts predominantly via its primary and secondary metabolites. This study investigates the possibility that sibutramine and/or its metabolites could act directly on white adipose tissue to increase lipolysis. Adipocytes were isolated by a collagenase digestion procedure from homozygous lean (+/+) and obese-diabetic ...

Animal studies have demonstrated the effects of insulin on central nervous system (CNS) functions such as cognition and control of adiposity, but human studies of insulin's CNS effects are more difficult to interpret. Peripheral insulin administration, which increases CNS insulin levels, is associated with increased insulin-stimulated glucose disposal and the ...

BACKGROUND: One of the outcomes positively associated with dioxin exposure in humans is type 2 diabetes. OBJECTIVES: This study was conducted in order to find the molecular biological evidence for the diabetogenic action of dioxin in adipose samples from Vietnam veterans. METHODS: We obtained 313 adipose tissue samples both from ...

The purpose of this work is to report soft tissue calcifications in severely diabetic patients that simulate venous stasis or scleroderma, without other stigmata of these diseases. Findings from lower extremity radiographs were reviewed on two patients with severe diabetes mellitus and abnormal soft tissue calcifications. Findings were correlated with ...

Peroxisome proliferator-activated receptor (PPAR)gamma is a key transcription factor facilitating fat deposition in adipose tissue through its proadipogenic and lipogenic actions. Human patients with dominant-negative mutations in PPARgamma display lipodystrophy and extreme insulin resistance. For this reason it was completely unexpected that mice harboring an equivalent mutation (P465L) in PPARgamma ...

Lipin-alpha and -beta are the alternatively spliced gene products of the Lpin1 gene, whose product lipin is required for adipocyte differentiation. Lipin deficiency causes lipodystrophy, fatty liver, and insulin resistance in mice, whereas adipose tissue lipin overexpression results in increased adiposity but improved insulin sensitivity. To assess lipin expression and ...

Studies in mice suggest that adipocytes serve as glucose sensors and regulate systemic glucose metabolism through release of serum retinol-binding protein 4 (RBP4). This model has not been validated in humans. RBP4 was highly expressed in isolated mature human adipocytes and secreted by differentiating human adipocytes. In contrast to the ...

BACKGROUND: Although insulin resistance in thyroid hormone excess is well documented, information on insulin action in hypothyroidism is limited. METHODS: To investigate this, a meal was given to 11 hypothyroid (HO; aged 45 +/- 3 yr) and 10 euthyroid subjects (EU; aged 42 +/- 4 yr). Blood was withdrawn for ...

Obesity is characterized by a low-grade inflammatory state, which could play a role in insulin resistance. Dynamic strength training improves insulin sensitivity. The objective of this study was to investigate, in obese subjects, whether the insulin sensitizing effect of dynamic strength training is associated with changes in plasma levels and ...

This study was designed to understand the cellular mechanisms responsible for defects in the insulin-stimulated signal transduction pathway in a type 2 diabetic animal model. We examined the in vitro PC-1 phosphodiesterase activity and glucose uptake in adipose tissue of streptozotocin (STZ)-induced type 2 diabetic rats. The PC-1 activity was ...

OBJECTIVE: Adiponutrin is a new transmembrane protein specifically expressed in adipose tissue. In obese subjects, short- or long-term calorie restriction diets were associated with a reduction in adiponutrin gene expression. Adiponut.rin mRNA level was previously shown to be negatively correlated with fasting glucose plasma levels and associated with insulin sensitivity ...

Our objective was to delineate the potential role of adipogenesis in insulin resistance and type 2 diabetes. Obesity is characterized by an increase in adipose tissue mass resulting from enlargement of existing fat cells (hypertrophy) and/or from increased number of adipocytes (hyperplasia). The inability of the adipose tissue to recruit ...

White adipose tissue (WAT) is now recognized as a highly active metabolic tissue and important endocrine organ producing numerous peptides and proteins with broad biological activity. The term adipokines has been coined to refer to a series of adipocyte-derived biologically active molecules, which may influence the function as well as ...

We studied how carbon monoxide (CO) is distributed within the human body through quantitation of CO concentrations in postmortem tissue samples from fatalities including possible CO exposure. Stored, frozen tissues were diced, sonicated in water, and 0.01-8.0 mg wet weight (ww) tissues were incubated with sulfosalicylic acid in CO-purged, septum-sealed ...

Catecholamines and natriuretic peptides stimulate human adipocyte lipolysis through an increase in cAMP and cGMP levels, resulting in phosphorylation and activation of hormone-sensitive lipase. A defect in hormone-sensitive lipase expression might contribute to the resistance to catecholamine-induced lipolysis observed in obesity. The respective roles and regulation of hormone-sensitive lipase and ...

The effects of oral niacin-bound chromium (NBC) supplementation on the subcutaneous fat tissue of type 2 Lepr(db) obese diabetic mice were examined using high-density comprehensive mouse genome (45,101 probe sets) expression arrays. The influence of such supplementation on the plasma cardiovascular risk factors of these mice was also investigated. Supplementation ...

White adipose tissue (WAT) represents a reservoir of lipophilic environmental pollutants, especially of those which are resistant to biological and chemical degradation - so-called persistent organic pollutants (POPs). Large amounts of different congeners and isomers of these compounds exhibit a variety of adverse biological effects. Interactions among different classes of ...

A high-fat diet (HFD) is associated with reduced glucose uptake in muscle, but not in adipose tissue. In the present study, we investigated whether a HFD can modulate glucose uptake in adipose tissue by increasing signal transduction through the CAP/Cbl pathway, independently of the PI3-K/Akt pathway. Our results suggest that, ...

CONTEXT: Hyperglycemia and insulin resistance frequently occur in critically ill patients even without a history of diabetes. OBJECTIVE: Our objective was to study the role of adipose tissue hormonal production in the development of insulin resistance in cardiac surgery patients. PARTICIPANTS, INTERVENTIONS, AND SETTINGS: Fifteen patients with elective cardiac surgery ...

Acyl-coenzyme A:diacylglycerol transferase (DGAT), fatty acid synthetase (FAS), and LPL are three enzymes important in adipose tissue triglyceride accumulation. To study the relationship of DGAT1, FAS, and LPL with insulin, we examined adipose mRNA expression of these genes in subjects with a wide range of insulin sensitivity (SI). DGAT1 and ...

Lipids are important body constituents that are vital for cellular, tissue, and whole-body homeostasis. Lipids serve as crucial membrane components, constitute the body's main energy reservoir, and are important signaling molecules. As a consequence of these pleiotropic functions, many common diseases, including atherosclerosis, chronic inflammatory disorders, and obesity, have been ...

The administration of oral aspirin within 48 h and tissue plasminogen activator within 3 h of ischaemic stroke onset remain the only treatments that have been shown to have clinical benefit. There has been much excitement about neuroprotection over the last two decades, as it may minimise the harmful effects ...

BACKGROUND: Increased prostaglandin E2 (PGE2) release has been suggested to contribute to the enhanced nociceptor sensitivity that underlies chronic osteoarthritis pain. We have previously shown increased levels of lactate and glycerol in synovium postoperatively. Thus, we wanted to investigate whether the local trauma response is related to subjective pain. METHODS: ...

AIMS/HYPOTHESIS: Adipose tissue inflammation has recently been implicated in the pathogenesis of insulin resistance and is probably linked to high local levels of cytokines. IL1B, a proinflammatory cytokine, may participate in this alteration. MATERIALS AND METHODS: We evaluated the chronic effect (1-10 days) of IL1B (0.1-20 ng/ml) on insulin signalling ...

A reduced brown adipose phenotype in white adipose tissue (WAT) may contribute to obesity and type 2 diabetes in humans. Retinoic acid, the carboxylic form of vitamin A, triggers in rodents a reduction of body weight and adiposity and an increased expression of uncoupling proteins in brown adipose tissue and ...

BACKGROUND: The cytokine response to operative trauma may be altered in obesity. Thus, we monitored changes in systemic and adipose tissue content of interleukin 6 (IL-6) and in insulin resistance in nonobese versus severely obese patients before and immediately after abdominal operations. METHODS: At the beginning and the end of ...

OBJECTIVE: C-Reactive Protein (CRP), a nonspecific marker of inflammation that is moderately elevated in obesity, metabolic syndrome (MS), and type 2 diabetes, has been proposed as a surrogate marker of nonalcoholic steatohepatitis (NASH). Its clinical usefulness in the diagnosis of NASH was evaluated in severely obese patients without or with ...

OBJECTIVE: Proteins involved in cellular fatty acid (FA) uptake and metabolism may be of relevance in the context of disturbed FA metabolism associated with insulin resistance. Therefore this study investigated relationships between FA handling protein mRNA expression in adipose tissue, FA composition of adipose tissue and serum, and markers of ...

Impaired oxidative phosphorylation is suggested as a factor behind insulin resistance of skeletal muscle in type 2 diabetes. The role of oxidative phosphorylation in adipose tissue was elucidated from results of Affymetrix gene profiling in subcutaneous and visceral adipose tissue of eight nonobese healthy, eight obese healthy, and eight obese ...

Recent studies suggest that adipose tissue hormones ("adipokines") are involved in the pathogenesis of various complications of obesity, including hyperlipidemia, diabetes mellitus, arterial hypertension, atherosclerosis, and heart failure. Apelin and visfatin are two recently described adipokines, although they are also synthesized outside adipose tissue. Apelin exists in at least three ...

CONTEXT: Visfatin was recently identified as a protein highly expressed and secreted in adipose tissue with insulin-mimetic effect and is a candidate hormone to help explain the association among adipose tissue expansion, insulin resistance, and type 2 diabetes. OBJECTIVE: The objective of the study was to assess expression of visfatin ...

Adipocytes secrete a variety of bioactive molecules that affect the insulin sensitivity of other tissues. We now show that the abundance of monocyte chemoattractant protein-1 (MCP-1) mRNA in adipose tissue and the plasma concentration of MCP-1 were increased both in genetically obese diabetic (db/db) mice and in WT mice with ...

Glucose transporter ontogenesis is likely to play a key role in glucose uptake by foetal tissues in order to satisfy their energy requirements. We thus investigated developmental changes in the bovine heart and perirenal adipose tissue in two glucose transporter isoforms, namely GLUT1 and GLUT4, the latter being responsible for ...

OBJECTIVE: Data from rodents provide evidence for a causal role of 11beta-hydroxysteroid dehydrogenase type 1 (11beta-HSD-1) in the development of obesity and its complications. In humans, 11beta-HSD-1 is increased in subcutaneous adipose tissue (SAT) of obese patients, and higher adipose 11beta-HSD-1 was associated with features of the metabolic syndrome. To ...

The safest place to store lipids is the white adipose tissue, but its storage capacity may become saturated resulting in excess of fat "overspilled" to non-adipose tissues. This overspill of fat occurs in apparently opposite pathological states such as lipodistrophy or obesity. When the excess of energy is redirected towards ...

PURPOSE OF REVIEW: Lipodystrophies are rare inherited and acquired disorders characterized by the selective loss of adipose tissue. Despite marked phenotypic and genotypic heterogeneity, most lipodystrophic syndromes predispose to similar metabolic complications seen in patients with obesity, such as insulin resistance, diabetes mellitus, hepatic steatosis and dyslipidemia. The purpose of ...

Type 2 diabetes is a heterogeneous disease characterized by hyperglycemia and insulin resistance in peripheral tissues such as adipose tissue and skeletal muscle. This review focuses on obesity as one of the major environmental factors contributing to the development of diabetes. It has become evident that adipose tissue represents an ...

Adipose tissue is a critical regulator of energy balance and substrate metabolism, and synthesizes several different substances with endocrine or paracrine functions, which regulate the overall energetic homeostasis. An excessive amount of adipose tissue has been associated with the development of type 2 diabetes, premature atherosclerosis, and cardiovascular disease. It ...

The metabolic activity of tendinous tissues has traditionally been considered to be of limited magnitude. However, recent studies have suggested that glucose uptake increases in the force-transmitting tissues as a response to contractile loading, which in turn indicates an elevated tissue metabolism. The purpose of the present study was to ...

Lipoprotein lipase (LPL) is a key factor determining the clearance of triglycerides from the circulation. The enzyme activity is tissue-specifically regulated by insulin, but it is not clear yet how insulin regulates the total LPL activity in the circulation. To answer such question, we measured LPL activity using the intravenous ...

AIMS/HYPOTHESIS: We compared metabolic gene expression in adipose tissue and skeletal muscle from patients with type 2 diabetes and from well-matched healthy control subjects. We hypothesised that gene expression would be discordantly regulated when comparing the two groups. Our secondary aim was to determine the effect of Interleukin-6 (IL6) infusion ...

PURPOSE OF REVIEW: The environment created by modern industrialized societies has caused an unprecedented rise in the prevalence of obesity and obesity-related disorders, including hypertension. Mechanisms that underlie the development of hypertension in obese individuals are not very well understood; they are thought to involve activation of the sympathetic nervous ...

There is increasing evidence that the glycerol channel, aquaporin 7(AQP7), has an important role in adipose tissue formation and function--deletion of the gene in a mouse strain leads to obesity and diabetes type 2 if the mice are aged or fed earlier with a high-fat or sucrose diet. Can increased ...

The enzyme of semicarbazide-sensitive amine oxidase (SSAO) activity has been reported to be elevated in blood from diabetic patients. SSAO are widely distributed in plasma membranes of various tissues and blood plasma. SSAO-mediated production of toxic aldehydes has been proposed to be related to pathophysiological conditions. Cytotoxic metabolites by SSAO ...

The mechanisms that control energy homeostasis and tissue growth during development are closely linked through the insulin signal transduction pathway. Changes in the level of insulin and other hormones reflect the nutritional status of the animal to control circulating sugar levels and fat metabolism. Systemic defects in insulin responsiveness can ...

Resistin is a newly identified adipocyte secreted hormone belonging to a cysteine-rich protein family. It is expressed in white adipose tissues in rodents and has also been found in several other tissues in human. Insulin, glucose, many cytokines and anti-diabetic thiazolidinediones are regulators of resistin gene expression. Resistin was firstly ...

OBJECTIVE: Adipocytes secrete a series of acute phase proteins including serum amyloid A (SAA); the link with metabolic status is unknown. We studied the variations of expression of the SAA gene in adipose and liver tissues and of SAA serum levels, as well as their relationships with metabolic features during ...