How aldosterone-producing adrenal adenomas cause high blood pressure

Novel regulators of calcium fluctuations in the zona glomerulosa of the human adrenal, and their relevance to the control of aldosterone production

One cause of high blood pressure is a benign tumour in the adrenal gland which secretes aldosterone, the hormone regulating salt and water balance. The over- secreting tumour is called an aldosterone-producing adrenal adenoma (APA). To understand the underlying mechanisms that cause high blood pressure in APAs, Professor Brown and colleagues compared the genes expressed in cells producing aldosterone to cells producing a different but similar hormone, cortisol (both produced in the adrenal), and discovered that most of the genes modulate calcium, which finally regulates aldosterone production. Two genes, ANO4 and VSNL1, showed a marked increase in their expression in aldosterone producing cells and are the focus of this fellowship. Another interesting gene included in this proposed research is KCNK1 which codes for a protein that regulates potassium and that we have found to be mutated in a family with a history of APAs. This may explain the link between aldosterone, hypertension, low potassium, which is often present in these patients, and the heart rhythm disturbance atrial fibrillation (KCNK1 is also expressed in the heart's atria).