Endocrine Abstracts

Short synacthen tests (SST) are used to investigate patients with suspected HPA pathology and a rise of serum total cortisol > 550nmol/L is accepted as demonstrating sufficient cortisol reserve. However, cortisol is 80% bound to cortisol binding globulin (CBG) and therefore abnormal values of CBG can influence serum total cortisol used to interpret dynamic tests of the HPA axis. The free cortisol index (FCI) is a surrogate marker for serum free cortisol and is defined as s...

Adeno-associated virus (AAV) has been used to express GFP in a variety of tissues. AAV has a tropism for neurones and we have been using AAV-GFP to determine the anatomical localisation of gene transfer after injection into the hypothalami of Wistar rats. The long term aim is to use this viral vector as a tool for investigating the hypothalamic control of appetite, energy expenditure and pituitary function.Male Wistar rats were anaesthetised and injecte...

Hypothalamic Cocaine- and Amphetamine-regulated transcript (CART) is regulated by circulating glucocorticoids. In adrenalectomised rodents, CART expression is reduced in the arcuate nucleus. However, CART also modulates the hypothalamo-pituitary-adrenal (HPA) axis. Acute intracerebroventricular injection of CART peptide significantly increases plasma ACTH and corticosterone but the long-term actions of CART are unknown. The aim of these studies was to determine the effect of l...

Cocaine and amphetamine regulated transcript (CART) was originally isolated from rat brain but CART is also synthesized and stored in the anterior pituitary. The localisation and factors regulating pituitary CART synthesis are largely unknown.Using a specific assay for the pituitary form of CART, CART(55-102), CART-immunoreactivity was detectable in the medium of the corticotroph cell line, AtT-20 (1.73 ± 0.54 fmols per millilitre per 24h) but not in control medium....

Cocaine and amphetamine regulated-transcript (CART) is highly expressed in the hypothalamus and was originally reported to be an endogenous satiety peptide. Intracerebroventricular injection of CART can result in motor abnormalities and recent studies have demonstrated increased food intake after intra-nuclear CART administration. To help clarify the situation CART was over-expressed in the hypothalamus using recombinant adeno-associated virus (rAAV-CART). Recombinant adeno-as...

The hypothalamic peptide, cocaine and amphetamine regulated transcript (CART) was originally reported to act as an anorexigenic peptide. However, we have recently shown that CART injection into the hypothalamic arcuate nucleus (ARC), acutely stimulates food intake. Here, we characterise the role of arcuate nucleus CART in the long term regulation of food intake and brown adipose tissue (BAT) using i) repeated intra-arcuate injection of CART peptide [CART(55-102)] and ii) polye...

Most tests of the hypothalamo-pituitary-adrenal axis (HPA) use total cortisol measurements, although only free cortisol is biologically active. Total cortisol is 90% bound to cortisol binding globulin (CBG). CBG varies between individuals, is elevated by oestrogens and reduced by acute illness or surgery. Low CBG levels may result in individuals apparently failing such tests, and receiving inappropriate steroid replacement. We hypothesised that correcting total cortisol for CB...