Diuresis is the increased secretion of urine. It may also be defined as the physiologic process involved in the excessive urination. There are many reasons that lead to this condition. It may be due to an increased liquid intake. It could also be due to the action of a diuretic. It may also be a symptom of a disease, such as diabetes mellitus. In essence, the increased excretion of urine is the result of lower ADH levels, characterized by a higher water concentration in the urine. It is part of the homeostatic response of the body to regulate body water balance. A form of diuresis, called osmotic diuresis, is caused by the presence of osmotically active substances in the renal tubules, like glucose, urea, and sodium sulfate. These substances limit water reabsorption. Glucose, for instance, cannot be reabsorbed and therefore causes a build-up of osmotic pressure in the tubule. As a result, water cannot be absorbed but instead retained in the lumen. This leads to an increase in urine output, which further results in dehydration and polydipsia (excessive thirst). Synonym: polyuria.
- Ganong, William F. (2005). Review of Medical Physiology. McGraw-Hill Professional. p. 719.
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