Endocrine Abstracts

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...

Testicular feminised (Tfm) mice bear an X-linked, single base pair deletion in the gene encoding the classical androgen receptor(1) consequently these animals express a truncated, non-functional form of the receptor protein. Affected animals (XTfmY) are rendered insensitive to actions mediated via this receptor. The Tfm mouse is therefore an excellent model for studying non-genomic testosterone signalling mechanisms. Unfortunately, Tfm mice are also deficient in the...

Background: Testosterone acts as a coronary vasodilator, and improves myocardial ischaemia in men with coronary artery disease. The dilatory mechanism of testosterone is independent of the classical androgen receptor and also of the release of endothelial-derived vasodilators. The aim of the present study was to determine whether testosterone has any demonstrable calcium antagonistic action, and if so to determine whether this is via inhibition of voltage-operated calcium chan...

Background: Testosterone is a coronary vasodilator, and improves myocardial ischaemia in men with coronary artery disease. The dilatory mechanism of testosterone is independent of the classical androgen receptor and endothelial-derived vasodilators. The aim of this study was to determine whether testosterone increases cAMP production in vascular smooth muscle cells (VSMCs) derived from the primary culture of rat thoracic aortae or in a VSMC cell line (A7r5).<p class="abste...

Background: The testicular feminised (Tfm) mouse exhibits an X-linked single base-pair deletion in the gene encoding the androgen receptor. Gene transcription produces a truncated form of the receptor protein, which has a conformational change in the androgen binding site, preventing androgen binding. Affected male animals (XTfmY) are rendered androgen insensitive and 17-alpha hydroxylase deficient, a key enzyme in the steroidogenesis pathway. XTfmY males have reduced circulat...