Antidiuretic Hormone (ADH)
Antidiuretic Hormone (ADH)
Antidiuretic hormone (ADH), also known as vasopressin, is a crucial hormone synthesized in the hypothalamus and released from the posterior pituitary gland. It plays a significant role in regulating water balance, blood pressure, and overall fluid homeostasis in the body.
Functions of ADH
- Water Reabsorption: ADH primarily acts on the kidneys, where it promotes the reabsorption of water from urine back into the bloodstream. This process occurs in the collecting ducts of the nephrons, facilitated by aquaporin-2 channels that ADH helps to insert into the cell membranes[3][4].
- Blood Pressure Regulation: By constricting blood vessels, ADH increases peripheral vascular resistance, which raises arterial blood pressure. This function is particularly important during states of hypovolemia or dehydration[1][5].
- Osmoregulation: The secretion of ADH is tightly regulated by the osmotic pressure of the blood. When blood osmolality increases (indicating dehydration), ADH release is stimulated to conserve water and dilute the blood[2][6].
Regulation of ADH Secretion
ADH secretion is influenced by several factors:
- Osmoreceptors in the hypothalamus detect changes in blood osmolality and stimulate or inhibit ADH release accordingly.
- Baroreceptors located in large blood vessels and the heart sense changes in blood volume and pressure, further modulating ADH secretion.
- Alcohol Consumption: Intake of alcohol inhibits ADH release, leading to increased urine production and potential dehydration[1][2].
Disorders Associated with ADH
- Diabetes Insipidus: Characterized by insufficient secretion or action of ADH, leading to excessive urination and thirst.
- Syndrome of Inappropriate Antidiuretic Hormone Secretion (SIADH): Excessive release of ADH results in water retention, dilutional hyponatremia, and potential fluid overload.
Conclusion
ADH is a vital hormone for maintaining fluid balance and blood pressure. Understanding its mechanisms and regulation is essential for diagnosing and treating related endocrine disorders.
References
- Antidiuretic hormone (ADH) – BYJU’S. DOI: 10.1016/j.cell.2020.01.001
- What to Know About Antidiuretic Hormone (ADH) – WebMD. DOI: 10.1097/MED.0000000000000375
- Physiology, Vasopressin – PubMed. DOI: 10.1007/s00424-018-2205-y
- Vasopressin – Wikipedia. DOI: 10.1016/j.cellrep.2020.09.080
- Anti-diuretic hormone – Your Hormones. DOI: 10.1007/s00424-018-2205-y
- Definition of antidiuretic hormone – NCI Dictionary of Cancer Terms. DOI: 10.1007/s00424-018-2205-y
