The renin-angiotensin-aldosterone system (RAAS) is a hormonal interplay which releases hormones to regulate sodium and potassium balance (electrolytes), intravascular volume, and blood pressure (BP) in the body. It helps in regulation of systemic blood pressure, renal blood flow and glomerular filtration rate (GFR) in the body. Excessive activity of RAAS system increases risk of hypertension and cardiovascular disease. Anti-diuretic hormone (ADH), also known as Vasopressin helps maintain blood pressure by acting on kidneys and blood vessels, conserves fluid volume by reabsorption of water into the body and reducing urine output by kidney.
RAAS is primarily associated with the kidneys, but its activity also affects the brain, heart, blood vessels, and adrenal glands. If the RAAS activity increases due to disturbed hormonal secretions, there is increased risk of hypertension and cardiovascular disease. Hypertension frequently accompanies advancing CKD, and it is often improperly assumed as the cause rather than the effect of CKD. In CKD patients who have hypertension, doctor may prescribe anti hypertension medicines and diuretic medicines. Patients who in stage 3 of CKD should monitor blood pressure on a frequent basis and take anti hypertensive medicines as per doctor’s advice. It is better to buy and use home BP monitors and record the results in a diary.
Also, some dietary rules may be followed like low intake of salty food, light exercises, yoga for balance of endocrine glands, meditation, sufficient sleep, and sufficient rest must be taken by the patient. Still, if high blood pressure in excess of 180/120, inspite of regular anti RAAS, anti diuretic doses of drugs as prescribed, immediately get in touch with the doctor to change/ increase dose or for intake of other medicines. Strictly follow the doctor’s advise in such cases and do not subject the patient to any kind of stress, physical or mental.
Renin is an enzyme produced in kidney. It goes on to convert a protein produced in liver called angiotensinogen to active angiotensin I hormone which is further metabolized by enzymes in lungs (angiotensin converting enzymes-ACE) to produce angiotensin II. Following binding to its receptor, Angiotensin II has following effects:
- It constricts blood vessels increasing blood pressure
- It boosts releases Anti diuretic hormone (ADH) from pituitary gland which manages blood pressure and water reabsorption, boosts release of aldosterone production from adrenaline glands resulting in body retaining more sodium and losing potassium from kidneys (fluid imbalance)
- Puts pressure on kidneys for fluid reabsorption contributing to progressive renal function loss.
Higher concentrations of anti-diuretic hormone cause blood vessels to constrict (become narrower) and this increases blood pressure. Anti-diuretic hormone is made by special nerve cells found in an area at the base of the brain known as the hypothalamus. The nerve cells transport the hormone down their nerve fibres (axons) to the pituitary gland where the hormone is released into the blood stream. Alcohol prevents anti-diuretic hormone release which causes an increase in urine production and dehydration.