AQP2geenissä

AQP2geenissä refers to the gene encoding Aquaporin-2 (AQP2), a water channel protein primarily found in the principal cells of the renal collecting duct. This gene plays a crucial role in regulating water reabsorption in the kidneys, a process essential for maintaining the body's water balance and urine concentration.

The AQP2 gene is located on human chromosome 12. Its expression and function are tightly regulated, particularly by the hormone vasopressin (also known as antidiuretic hormone or ADH). Vasopressin binds to receptors on the surface of principal cells, triggering a signaling cascade that leads to the insertion of AQP2 water channels into the apical membrane of these cells. This insertion increases the permeability of the collecting duct to water, allowing it to move from the tubular fluid back into the bloodstream, thereby concentrating the urine and conserving body water.

Mutations in the AQP2 gene can lead to a variety of inherited nephrogenic diabetes insipidus (NDI) disorders. These conditions are characterized by the inability of the kidneys to concentrate urine, leading to excessive thirst (polydipsia) and the excretion of large volumes of dilute urine (polyuria). Different types of mutations can result in either a complete lack of functional AQP2 protein or a protein that is not properly targeted to the cell membrane, ultimately impairing water transport. Research into AQP2geenissä continues to advance our understanding of water homeostasis and the molecular basis of kidney disorders.