While the kidneys operate to maintain osmotic balance and blood pressure in the body, they also act in concert with hormones. Hormones are small molecules that act as messengers within the body. Hormones are typically secreted from one cell and travel in the bloodstream to affect a target cell in another portion of the body. Different regions of the nephron bear specialized cells that have receptors to respond to chemical messengers and hormones. Table summarizes the hormones that control the osmoregulatory functions.
|Hormones That Affect Osmoregulation|
|Epinephrine and Norepinephrine||Adrenal medulla||Can decrease kidney function temporarily by vasoconstriction|
|Renin||Kidney nephrons||Increases blood pressure by acting on angiotensinogen|
|Angiotensin||Liver||Angiotensin II affects multiple processes and increases blood pressure|
|Aldosterone||Adrenal cortex||Prevents loss of sodium and water|
|Anti-diuretic hormone (vasopressin)||Hypothalamus (stored in the posterior pituitary)||Prevents water loss|
|Atrial natriuretic peptide||Heart atrium||Decreases blood pressure by acting as a vasodilator and increasing glomerular filtration rate; decreases sodium reabsorption in kidneys|