Comment
Author: Admin | 2025-04-28
Particularly the peritubular capillaries. This reduces medullary osmolality and thus impairs the concentration of urine in the loop of Henle (which usually uses the high osmotic and solute gradient to transport solutes and water). Further, the limited tubular epithelial cell permeability increases osmolality and thus water retention in the filtrate.[10]It was previously believed that the primary mechanism of osmotic diuretics such as mannitol is that they are filtered in the glomerulus, but cannot be reabsorbed. Thus their presence leads to an increase in the osmolarity of the filtrate and to maintain osmotic balance, water is retained in the urine.[citation needed]Glucose, like mannitol, is a sugar that can behave as an osmotic diuretic. Unlike mannitol, glucose is commonly found in the blood. However, in certain conditions, such as diabetes mellitus, the concentration of glucose in the blood (hyperglycemia) exceeds the maximum reabsorption capacity of the kidney. When this happens, glucose remains in the filtrate, leading to the osmotic retention of water in the urine. Glucosuria causes a loss of hypotonic water and Na+, leading to a hypertonic state with signs of volume depletion, such as dry mucosa, hypotension, tachycardia, and decreased turgor of the skin. Use of some drugs, especially stimulants, may also increase blood glucose and thus increase urination.[citation needed].Low-ceiling diuretics[edit]The term "low-ceiling diuretic" is used to indicate a diuretic has a rapidly flattening dose effect curve (in contrast to "high-ceiling", where the relationship is close to linear). Certain classes of diuretic are in this category, such as the thiazides.[11]Mechanism
Add Comment