A patient is on a Low calcium diet for 6 weeks. He is most likely to have:
|A||Raised parathyroid hormone levels|
|B||Raised calcitonin levels|
|C||Increased phosphate levels|
|D||None of the above|
I. Circulating ionized calcium acts directly on the parathyroid glands in a negative feedback fashion to regulate the secretion of PTH.
II. The key to this regulation is a cell membrane Ca2+ receptor.
III. This serpentine receptor is coupled via a G protein to phosphoinositide turnover and is found in many tissues.
IV. In the parathyroid its its activation inhibits PTH secretion is habited and the Ca2+ is deposited in the bones.
V. When it is low, secretion is increased and Ca2+is mobilized from the bones.