Endocrine Abstracts

Aims/objectives: Glycerol cycling plays an essential regulatory role in metabolism in both health and disease. Aquaporins (AQPs) are a recently described family of water transporting membrane proteins, which contain a subset of members that also have the ability to transport glycerol across the cell membrane. This study sought to investigate the adipose tissue expression profile of AQPs in humans, and to assess the role of AQPs in adipocyte differentiation.<p class="abstex...

Apart from its role in energy storage, adipose tissue produces several hormones and cytokines termed ‘adipokines’ that have wide-ranging effects on carbohydrate and lipid metabolism; and thereby, play an important role in the pathogenesis of the metabolic syndrome. Visfatin is a novel adipokine, levels of which increase in obesity and is adipogenic; properties common to that of leptin. Thus, leptin may modulate visfatin production in adipose tissue. We investigated t...

NESFATIN-1 is a recently identified hypothalamic satiety molecule derived from its precursor protein, NEFA/nucleobindin2 (NUCB2). Although the hypothalamus is considered the cornerstone for maintenance of energy homeostasis, adipose tissue plays an important role in the integration of metabolic activity and energy balance; communicating with peripheral organs and the brain via secreted proteins, termed adipokines. Many hypothalamic satiety regulatory peptides have been describ...

Aims: Polycystic ovary syndrome (PCOS) is associated with insulin resistance, obesity and cardiovascular complications. Thrombospondin-1 (TSP-1) is a novel anti-angiogenic adipokine highly expressed in obese, insulin-resistant subjects. We sought to assess TSP-1 levels in adipose (AT) from PCOS women and matched controls. The effects of metformin treatment on circulating TSP-1 levels in PCOS subjects; effects of serum from normal and PCOS women on in vitro migration and...

Background: Secretory products from adipocytes may contribute to increased insulin resistance (IR). Retinol-binding protein-4 (RBP-4) may increase IR in mice, with elevated levels in insulin resistant mice and humans with obesity and type 2 diabetes. Mechanisms regulating RBP-4 synthesis remain not fully understood. It is not clear whether short-term hyperglycaemia alters RBP-4 levels in humans. In order to investigate this, we measured serum RBP-4 concentrations during 75 gra...

Polycystic ovary syndrome (PCOS) is associated with insulin resistance and obesity. Recent studies have shown that plasma omentin-1 levels decrease with obesity. Currently, no data exists on the relative expression and regulation of omentin-1 in adipose tissue (AT) of PCOS women.Objectives: To assess mRNA and protein levels of omentin-1 in omental (om) AT of PCOS women and matched controls, including circulating omentin-1. Ex vivo and in vivo</...

Orexins mediate a variety of physiological processes including feeding behaviour, the circadian pathway and cortisol secretion. Steroidogenesis is regulated by a variety of neuropeptides and one of the key rate-limiting steps is cholesterol transport across the mitochondrial membrane by the steroidogenic acute regulatory (StAR) protein. StAR expression can be regulated through several different signalling pathways. Despite the clear link between orexins and steroid production,...

Context: Polycystic ovary syndrome (PCOS) is associated with insulin resistance (IR) and obesity, both predisposing factors to type 2 diabetes. A very recently described adipokine, retinol-binding protein 4 (RBP-4), has been shown to modulate insulin signalling and possibly lead to IR. At present, there is no data that depict the relative expression of RBP-4 in either serum or adipose tissue of PCOS women.Objectives: In women with PCOS compared to matche...

Objective: Orexin-A and orexin-B and their G-protein coupled receptors (orexin receptor-1 & -2: OX1R, OX2R) have divergent effects on physiological behaviour, cardiovascular regulation, glucocorticoid and insulin release. Furthermore, orexins have been shown to affect both brown adipose tissue energy expenditure and thermogenesis through stimulation of sympathetic nerve activity. Despite in vivo studies demonstrating a role for orexins acting centrally on adipose ti...

Objective: Orexin-A and orexin-B and their G-protein coupled receptors (orexin receptor-1 & -2: OX1R, OX2R) have divergent effects on physiological behaviour, cardiovascular regulation, glucocorticoid and insulin release. Furthermore, orexins have been shown to affect both brown adipose tissue energy expenditure and thermogenesis through stimulation of sympathetic nerve activity. Despite in vivo studies demonstrating a role for orexins acting centrally on adipose ti...