Endocrine Abstracts

Besides playing a role in energy homeostasis, orexins have been reported to have divergent effects on physiological behaviour, cardiovascular regulation, glucocorticoid release, as well as playing a key role in the aetiopathogenesis of narcolepsy. Recent studies using rodent models suggest orexins may also be involved in the regulation of thermogenesis. For example, mice lacking the prepro-orexin gene are significantly hypophagic but have normal body weight suggesting differen...

Background, subjects & methods: Dexamethasone increases visfatin synthesis in vitro, but it is not clear, whether it is reflected in the changes of serum levels of this cytokine. We have therefore assessed fasting serum concentrations of visfatin, glucose, insulin and cortisol in 20 subjects (4 males, 5 subjects with type 2 diabetes) age (mean±S.D.) 42.1±17.2 years, BMI 36,7±8.38 kg/m2 before and after 48 hours of administrat...

Background, subjects & methods: Visfatin, also known as pre-B cell colony enhancing factor (PBEF), is a cytokine that is highly expressed in visceral fat, and exerts insulin-mimicking effects in rodents through activation of an insulin receptor, though in a manner distinct from insulin. Visfatin levels do not change in response to acute hyperinsulinaemia in mice, but it is not clear whether this also applies to humans. In order to investigate this we measured serum visfati...

Obesity is a risk factor for the metabolic syndrome and type 2 diabetes. Adiponectin, a 30 kDa peptide secreted from adipocytes has been shown to be anti-atherogenic, and anti-inflammatory, as well as affecting insulin resistance and pancreatic beta-cell function. This study investigated the levels of expression of the adiponectin receptor subtypes 1 and 2 (AdR-1 and AdR-2) and regulation of their expression in the pancreatic BRIN-BD11 beta-cells line. Cells were cultured in R...

Orexin-A (OR-A) and orexin-B (OR-B) play an important role in the regulation of energy balance and the control of sleep-wake cycle. They act via G-protein coupled receptors, namely orexin receptor-1 (OX1R) and orexin receptor-2 (OX2R). OX2R has equal affinity for both OR-A and OR-B, whilst OX1R has a 10-fold greater affinity for OR-A. Orexin-mediated functions have been extensively explored, however, the intracellular signalling pathways remain poorly understood. Using HEK-293...

Obesity is linked to the development of insulin resistance, diabetes and an increased risk of cardiovascular disease and the metabolic syndrome. Adipose tissue-derived proteins so termed ‘adipokines’ have been implicated in cardiovascular disease and the metabolic syndrome although the molecular mechanisms are not fully understood. Adiponectin, unlike other adipokines, has been shown to have anti-inflammatory, anti-atherogenic, and insulin-sensitising effects. Import...

A 25 year old lady was referred to the endocrine clinic after her newborn baby was noted to have respiratory problems, marked osteopenia and hypocalcemia. Further investigations on the mother showed corrected calcium of 1.11 mmol/L; however she was relatively asymptomatic. Reviewing her history in detail, she was born in Nigeria and moved to the UK 2 years prior to the presentation. She used to get intermittent cramps in her hands, legs and body since the age of 10 in addition...

One of the hallmarks of parturition in most mammals is a dramatic drop in plasma levels of progesterone (P4), which promotes myometrial relaxation, prior to labor. In humans and some other primates however, the opposite occurs and placental P4 production increases with advancing pregnancy. The expression of nuclear progesterone receptor (PR)-responsive genes is decreased in the primate uterus at term, which suggests ‘functional’ progestin withdrawal involves repressi...

The family of G-protein coupled receptors (GPCRs) are amongst the best-described regulators of cardiovascular pathophysiology. In rodents, intracerebroventricular administration of orexins increases mean arterial pressure and heart rate. However, important peripheral actions of orexins and their cognate receptors is now increasingly of interest.In this study we demonstrated that both receptors are present across the rat heart, at mRNA and protein level. ...

Pregnancy, a state of insulin resistance (IR), is associated with elevated levels of cytokines and profound alterations in metabolism, directed towards supplying adequate nutrition for the fetus. Adiponectin, an adipokine with anti-inflammatory and insulin sensitising properties, plays an important role in energy homeostasis. Interestingly, in gestational diabetes mellitus (GDM), a state of greater insulin resistance, serum adiponectin levels are lower than normal subjects. We...