
the isolation of thyrocalcitonin and study of its effects in the rat.
   the thyroid secretes a
polypeptide hormone (thyrocalcitionin)
which is effective
in lowering plasma calcium
and phosphate.  the hormone
can be extracted from
the thyroid of the rat, dog,
pig, goat, ox, and monkey.
the isolation of the hormone
from pig thyroid by a combination
of salt fractionation
and gel filtration is described.
one microgram of
the pure material is very
active in the rat.  thyrocalcitonin
remains effective after
parathyroidectomy, after
nephrectomy, after overdosage
with vitamin d, during vitamin
d deficiency, and during
calcium or magnesium deficiency.
its action is not prevented
by prior administration
of actinomycin d.  a
single injection does not change
soft tissue calcium but
infusion for 12 hr lowers cardiac
muscle calcium.  it is
concluded that this new thyroid
hormone acts on bone
and that it probably plays an
important role in normal physiology.
