Endocrine Abstracts

Large animals are increasingly used a models for endocrine research. Unlike rodents they are cortisol-dominant and thus more similar to humans. In this study we use two novel analytical methods to compare the steroid profile of pigs, sheep and humans; 1. Simultaneous quantification of primary glucocorticoids, glucocorticoid precursors and mineralocorticoids in plasma (>20 steroids); 2.Quantification of glucocorticoids metabolites (>10 ...

Circulating estrogens decrease after the menopause from 60–400 to 5–30 pg/ml in postmenopausal women and in men are below 30 pg/ml. These low physiological concentrations present an analytical challenge. Analysis of steroids by tandem mass spectrometry is attractive due to its high specificity compared with immunoassays. However, estrogens do not ionise efficiently and therefore chemical modifications are necessary to achieve the sensitivity required.<p class="ab...

The glucocorticoid hormone, cortisol, regulates fuel metabolism, inflammation and stress–responses. Its circulating concentrations are tightly controlled by the hypothalamic–pituitary–adrenal axis. However, 11β-hydroxysteroid dehydrogenase 1 (11βHSD1) generates additional cortisol in tissues, by reduction of inert cortisone. Using a tracer (9,11,12,12[2H]4-cortisol; d4-cortisol), the velocity of 11βHSD1 can be determined as t...

BackgroundObesity is closely associated with impaired adipose tissue function. Although bariatric surgery is the treatment of choice for severe obesity and its related conditions, there are conflicting data on the reversal of adipose tissue dysfunction after surgery-induced weight loss. We hypothesise that local steroid hormone availability influences fat deposition or mobilisation and that these changes track with weight loss improvements, because plasm...

Liquid Chromatography tandem mass spectrometry (LC–MS/MS) is gold-standard for androgen analysis in biological fluids, superseding immunoassays in specificity, particularly at low concentrations. While LC–MS/MS is well established for analysis of testosterone (T) and androstenedione (A4), 5α-dihydrotestosterone (DHT) presents greater analytical challenges. DHT circulates at low nanomolar concentrations in men and lower in women, ionising inefficiently. Thus, eve...

Cell autonomous sex identity (CASI) of birds is the concept that sex-steroids have little or no effect on the development of secondary sexual characteristics in birds, and that sexual dimorphisms are determined by the sex-chromosome content of cells in individual tissues. In avian species males have a ZZ sex chromosome, while females are ZW. Sexual dimorphisms in chickens, such as muscle mass, comb and wattle size and hackles and spur development are believed to be determined ...