Structure:
Calcitonin from the parafollicular, or C cells of the thyroid
gland, is a polypeptide. High blood levels of Ca++ act as a humeral
stimulus for releasing calcitonin, and lower levels reduce release.
Function:
Calcitonin is especially important during youth, when the bones
are growing rapidly. Calcitonin has a bone-sparing effect, by reducing
bone resorption, and stimulating Ca++ uptake
from dietary sources, and the
circulation.
