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Aldosterone is the main mineralocorticoid steroid hormone produced by the zona glomerulosa of the adrenal cortex in the adrenal gland. [ 4 ] [ 5 ] It is essential for sodium conservation in the kidney, salivary glands, sweat glands, and colon. [ 6 ]
The collecting duct system of the kidney consists of a series of tubules and ducts that physically connect nephrons to a minor calyx or directly to the renal pelvis.The collecting duct participates in electrolyte and fluid balance through reabsorption and excretion, processes regulated by the hormones aldosterone and vasopressin (antidiuretic hormone).
These blood vessels supply a network of small arteries within the capsule of the adrenal glands. Thin strands of the capsule enter the glands, carrying blood to them. [8] Venous blood is drained from the glands by the suprarenal veins, usually one for each gland: [8] The right suprarenal vein drains into the inferior vena cava.
Aldosterone causes the renal tubules to increase the reabsorption of sodium which in consequence causes the reabsorption of water into the blood, while at the same time causing the excretion of potassium (to maintain electrolyte balance). This increases the volume of extracellular fluid in the body, which also increases blood pressure.
Regardless of the cause, sequestration of fluid within the abdomen leads to additional fluid retention by the kidneys due to stimulatory effect on blood pressure hormones, notably aldosterone. The sympathetic nervous system is also activated, and renin production is increased due to decreased perfusion of the kidney.
The primary mineralocorticoid, aldosterone, is produced in the adrenocortical zona glomerulosa by the action of the enzyme aldosterone synthase (also known as CYP11B2). [ 4 ] [ 5 ] Aldosterone is largely responsible for the long-term regulation of blood pressure . [ 6 ]
The opposite mechanism is called transrepression. The hormone receptor without ligand binding interacts with heat shock proteins and prevents the transcription of targeted genes. Aldosterone and cortisol (a glucosteroid ) have similar affinity for the mineralocorticoid receptor; however, glucocorticoids circulate at roughly 100 times the level ...
ADH is part of the control of fluid balance. Its levels in the blood vary with the osmolality of the plasma, which is measured in the hypothalamus of the brain. Aldosterone's action on the kidney tubules prevents sodium loss to the extracellular fluid (ECF). So there is no change in the osmolality of the ECF, and therefore no change in the ADH ...