Endocrine Abstracts

Background: 11β-hydroxysteroid dehydrogenases (11β-HSD1&2) interconvert cortisol (F) and cortisone (E). Although 11β-HSD1 reductase activity has been measured in vivo, E production (dehydrogenase activity) has not been quantified using a Gold Standard technique, steady state tracer infusion.Aim: To develop a method to measure E production in vivo using the stable isotope tracer d2-cortisone (d2E).Me...

Studies in rats suggest that androgens are involved in sex-specific differences in blood pressure. In human studies there is no difference in blood pressure between boys and girls, but following puberty, men present with a higher blood pressure than women. Modulation of sodium reabsorption through the ENaC is an important component in the control of sodium balance. This is clearly demonstrated by rare genetic disorders of sodium-channel activity (Liddle's syndrome and pseudohy...

The crucial role of vitamin D in mineral homeostasis is well known. However recent evidence has documented its importance for immunomodulation and inflammation. The kidney is the main source for the endocrine synthesis of the active metabolite 1,25-dihdroxyvitamin D3 (1,25D3), with expression of the key enzyme, 25-hydroxyvitamin D 1alpha-hydroxylase (1alpha-OHase). Our aim was to investigate the alteration of the vitamin D hormonal system in renal failure and assess the impact...

The functions of dendritic cells (DCs) are tightly regulated such that protective immune responses are elicited and unwanted immune responses are prevented. 1,25-dihydroxyvitamin D3 (1,25(OH)2D3) has been identified as a major factor that inhibits the differentiation and maturation of DCs, an effect dependent upon its binding to the nuclear vitamin D receptor (VDR). Physiological control of 1,25(OH)2D3 levels is dependent upon the enzyme 25-hydroxyvitamin-D3-1alpha-hydroxylase...

Studies in vitro have highlighted the potent anti-cancer effects of the active form of vitamin D, 1,25-dihydroxyvitamin D3 (1,25D3). However, the in vivo application of 1,25D3 and its synthetic analogs remains problematical due to persistent hypercalcaemic side-effects. Recent studies have shown that it may be possible to overcome this in an autocrine fashion via extra-renal synthesis of 1,25D3. In particular, analysis of prostate and co...