Aldosterone acts on which part of kidney

It is biosynthesized from cholesterol and makes use of aldosterone synthase a steroid hydroxylase cytochrome P enzyme located in the zona glomerulosa.

The biosynthesis of aldosterone is stimulated by the following factors: 1 increase in angiotensin III levels in the plasma, 2 increase in plasma angiotensin II, ACTH, or potassium levels, 3 plasma acidosis, 4 adrenoglomerulotropin promotes aldosterone secretion , and 5 stretch receptors stimulating the release of aldosterone from the adrenal gland, particularly when blood pressure is decreased.

Aldosterone acts on the kidney s, particularly involved in the reabsorption of sodium as well as the passive reabsorption of water. It is also associated with lowering the plasma potassium concentration. It does so through the following mechanisms: 1. With these biological actions of aldosterone, it is associated in the increase of blood pressure and blood volume. In high levels though, it causes sodium retention, high blood pressure, heart rhythm irregularities, and possibly paralysis.

The condition wherein there is an abnormally high aldosterone level is referred to as hyperaldosteronism whereas the condition in which the level of aldosterone is abnormally decreased is called hypoaldosteronism. IUPAC name:. Reference s : 1 Aldosterone. Knowing these effects should quickly suggest the cellular mechanism of action this hormone.

Aldosterone stimulates transcription of the gene encoding the sodium-potassium ATPase, leading to increased numbers of " sodium pumps " in the basolateral membranes of tubular epithelial cells. Aldosterone also stimulates expression of a sodium channel which facilitates uptake of sodium from the tubular lumen. Aldosterone has effects on sweat glands, salivary glands and the colon which are essentially identical to those seen in the distal tubule of the kidney. The major net effect is again to conserve body sodium by stimulating its resorption or, in the case of the colon, absorption from the intestinal lumen.

Conservation of water follows conservation of sodium. Control over aldosterone secretion is truly multifactorial and tied into a spider web of other factors which regulate fluid and electrolyte composition and blood pressure.

If the major effects of aldosterone are considered, it is rather easy to predict factors which stimulate or suppress aldosterone secretion. Other factors which stimulate aldosterone secretion include adrenocorticotropic hormone short-term stimulation only and sodium deficiency. Factors which suppress aldosterone secretion include atrial naturetic hormone , high sodium concentration and potassium deficiency. A deficiency in aldosterone can occur by itself or, more commonly, in conjunction with a glucocorticoid deficiency, and is known as hypoadrenocorticism or Addison's disease.

Without treatment by mineralocorticoid replacement therapy, a lack of aldosterone is lethal, due to electrolyte imbalances and resulting hypotension and cardiac failure.

Since it circulates at about the same K m binding affinity for renin, small changes would markedly affect the generation of angiotensin I. Angiotensin II increases blood pressure by causing vasoconstriction of the arterioles and is the most potent vasoactive substance known.

Angiotensin II inhibits renin release in a short feedback loop and is a potent stimulator of aldosterone production. Stored in granules of atrial myocytes.