Endocrine Abstracts

Background: A polymorphism within the CYP11B2 gene, characterised by a C/T substitution at position 344, the putative binding site for steroidogenic transcription factor1, has been shown to influence aldosterone excretion rate and blood pressure in essential hypertension.Aims: Assess the effect of contrasting genotype for the SF1 site on urinary and plasma steroid production during dietary manipulation of the renin-angiotensin system and assess the press...

There is no consensus on the role of insulin secreted from pancreatic β-cells in regulating its own secretion, nether in rodent islets nor in human islets. We have now investigated whether there is an autocrine signalling role for insulin in human islets by determining insulin receptor expression and assessing the effects of insulin receptor activation using a non-peptidyl insulin-mimetic termed L-783,281. All experiments used hand-picked human islets of Langerhans. Human...

Peroxisome proliferator-activated receptor (PPAR) alpha is one of three PPARs (alpha, beta (delta) and gamma), which are distinguished by distinct lipid and eicosanoid ligands. All three PPARs are present in pancreatic islets. PPARalpha expression and/or activity is important in the regulation of tissue triacylglycerol (TAG) content and fatty acid oxidation (FAO). PPARalpha binds the hypolipidaemic fibrates and promotes FA-mediated up-regulation of FAO. Surplus FA normally up-...

Aim: To identify the role of unmetabolised arachidonic acid (AA) produced by phospholipase A2 (PLA2) enzymes, and its 12-lipoxygenase (12-LOX) and cyclooxygenase (COX) products in the insulin secretory response of human islets of Langerhans. Material and Methods: Expression of COX-1 and COX-2 mRNAs was determined by RT-PCR. Insulin secretion from perifused human islets was measured by radioimmunoassay, in the presence of inhibitors of PLA<su...

Background: Current evidence suggests that testosterone acts as a vasodilator in several vascular beds. This may have implications for men who are androgen deficient, in whom vascular reactivity may be impaired. We have studied vascular responses in vitro in femoral arteries from testicular feminised mice (Tfm), which lack a functional androgen receptor and are consequently androgen resistant and have reduced circulating levels of testosterone. Methods: Femoral arteries from m...