Potassium sparing diuretics

Diuretics are medications that act on the kidneys to increase production of urine, and to eliminate water, certain metabolic wastes, and electrolytes from the body.

There are 5 main types of diuretics; carbonic anhydrase inhibitors, osmotic diuretics, thiazide and thiazide-like diuretics, loop diuretics,, and last but not least, potassium sparing diuretics - which is the only class of diuretic that retains potassium, rather than wasting it.

Now, the basic unit of the kidney is called a nephron, and each nephron is made up of a glomerulus, which filters the blood. T.

The filtered content then goes through the renal tubule, where excess waste, and molecules, such as ions and water, are removed or filtered through an exchange between the tubule and the peritubular capillaries.

So the renal tubule plays a huge role in secretion and reabsorption of fluid and ions - such as sodium, potassium, chloride, and magnesium - in order to maintain homeostasis - or the balance of fluid and ions in our body.

The renal tubule has a few segments of its own: the proximal convoluted tubule, the U-shaped loop of Henle, with a thin descending, a thin ascending limb, and a thick ascending limb, and finally, the distal convoluted tubule, which empties into the collecting duct, which collects the urine.

Different kinds of diuretics act on different segments of the renal tubule. Now, potassium sparing diuretics act on the cortical collecting tubules. Here, there are principal cells and α-intercalated cells dispersed amongst the tubule cells.

The principal cell has two pumps on the apical surface, an ATP-dependent potassium pump that pushes potassium into the tubule, and an epithelial sodium channel pump, called ENaC for short, that pulls sodium into the cell.