home / medterms medical dictionary a-z list / cdc definition Medical Definition of CDC CDC: The Centers for Disease Control and Prevention, the US agency charged with tracking and investigating public health trends. A part of the US Public Health Services (PHS) under the Department of Health and Human Services (HHS), the CDC is based in Atlanta, Georgia. It publishes key health information, including weekly data on all deaths and diseases reported in the US and travelers' health advisories.
An aldosterone test measures the level of aldosterone (a hormone made by the adrenal glands), in the blood. Aldosterone helps regulate sodium and potassium levels in the body. This helps control blood pressure and the balance of fluids and electrolytes in the blood. The kidney hormone renin normally stimulates the adrenal glands to release aldosterone.
Aldosterone is a steroid secreted by the cortex of the adrenal gland. It is. the most potent hormone regulating the body's electrolyte balance. Aldosterone acts directly on the kidney to decrease the rate of sodium-ion excretion (with accompanying retention of water), and to increase the rate of potassium-ion excretion. The secretion of aldosterone appears to be regulated by two mechanisms. First, the concentration of sodium ions may be a factor since increased rates of aldosterone secretion are found when dietary sodium is severely limited. Second, reduced blood flow to the kidney stimulates certain kidney cells to secrete the proteolytic enzyme renin, which converts the inactive angiotensinogen globulin in the blood into angiotensin I. Another enzyme then converts angiotensin I into angiotensin II, its active form. This peptide, in turn, stimulates the secretion of ...