Endocrine Abstracts

Acute intermittent porphyria (AIP) is an autosomal dominant disease due to deficient Porphobilinogen (PBG) deaminase activity. Hyponatremia, found in approximately 20% of symptomatic AIP, is often due to inappropriate ADH secretion (SIADH). An association between AIP and hyperthyroidism is not clearly established. We describe a patient with AIP and SIADH who presented with Graves’ hyperthyroidism. A 35-year-old lady was admitted with lower abdominal pain. Physical examina...

Vascular smooth muscle cells (VSMC) form a major constituent of the atherosclerotic plaque providing structural stability. However, increased cell number due to high proliferation rates can lead to greater artery occlusion. Testosterone replacement therapy improves exercise capacity and reduces symptoms of angina in men with coronary artery disease, although its effect upon VSMC growth is currently unknown. Testosterone deficiency is associated with increased atheroma burden a...

Several studies have demonstrated that atherosclerosis is associated with low serum levels of testosterone and replacement therapy reduces myocardial ischaemia in men. Vascular smooth muscle cell (VSMC) apoptosis reduces plaque stability. The role of testosterone if any, in this process is unknown. Testosterone has been demonstrated act via both the classic androgen receptor and by calcium channel antagonism. Calcium channel blockers have been shown to induce VSMC apoptosis. W...

Testosterone therapy has been shown to benefit men with heart failure or coronary artery disease, an activity proposed to be mediated via its vasodilatory efficacy. Testosterone has been demonstrated to dilate human coronary arteries, but it is unknown whether testosterone has a similar action in human pulmonary or systemic vessels.Male patients were recruited from cardiothoracic (n = 14, age = 68 plus/minus 9) or gastrointestinal (n = 8, age = 70 plus/minus 3) operating l...

69-year-old male with background of hypertension and dyslipidaemia was admitted to ENT with a food bolus obstruction. CXR on admission revealed a well-defined mass in the right lower lobe consistent with lung cancer. Oesophagoscopy revealed a narrowing level secondary to external compression. A staging CT of chest and abdomen confirmed a mass on the right base invading the main right lower lobe bronchus. Incidentally there was an 8 cm infra renal abdominal aortic aneurysm. The...

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...

Low testosterone levels in men are associated with increased atherosclerosis, and testosterone replacement therapy has been shown to reduce myocardial ischemia in men with coronary artery disease. Vascular smooth muscle cell (VSMC) apoptosis is proposed to reduce plaque stability, but the role of testosterone in this process is unknown. Testosterone causes vasodilatation via calcium channel antagonism and the calcium channel antagonist nifedipine induces VSMC apoptosis. We hav...

Atherosclerotic plaque smooth muscle cells (SMCs) are sensitive to apoptotic stimuli, increasing plaque instability. Testosterone replacement therapy is beneficial in men with coronary artery disease, although its effect upon plaque stability is unknown. We have utilised the rat A7r5 vascular SMC line to investigate the effects of testosterone on apoptosis induced by serum deprivation or the calcium channel antagonist nifedipine.Cells were plated at 1500...

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...

Introduction: Low endogenous testosterone is associated with atherosclerosis in elderly men. The aim of this study was to determine whether an inactive androgen receptor (AR) coupled with testosterone deficiency, inherent to the testicular feminised (Tfm) mouse, is associated with atherosclerosis following cholesterol feeding.Methods: Eight-week-old Tfm (n=34) and XY (n=32) littermate controls were fed for 16, 20, 24 or 28 weeks on either diet 1 (compris...