Blood Levels of Hormones will depend on:
- The rate of secretion, which may be divided into:
- the rate of synthesis, dependent on chemical precursors from diet or from other cells in the body.
- the rate of release of preformed hormone into the blood, dependent on the stimulus for release.
- The rate of removal, which may be divided into:
- the rate of inactivation, dependent on the rate at which the hormone is used up at its site of action or rendered inactive during passage through the liver or kidney.
- the rate of excretion, dependent upon renal handling of either the inactivated hormone or its metabolic breakdown products (often used as a basis for "drug" testing).