7. THE ULTIMOBRANCHIAL GLANDS
387
zation and the Adopted Names Council of the American Medical
Association.
A. History
The history of the calcitonin field was reviewed recently by Copp
(1967). The hormone was discovered in 1961 (Copp et al., 1961, 1962)
when it was shown that high calcium perfusion of the thyroid-parathyroid
gland complex in the dog released a potent hypocalcemic factor. This
work was subsequently confirmed by Kumar et al. (1963). The name
“calcitonin” was proposed for the hormone because it was apparently involved in regulating the tone of calcium in body fluids. Although the hormone was originally thought to come from the parathyroids, Hirsch et al.
(1963) showed that a potent hypocalcemic substance could be extracted
from rat thyroid. They tentatively proposed the alternative name “thyrocalcitonin” to indicate the gland of origin and the possible identity with
calcitonin. In immunofluorescent studies with antibodies to porcine calcitonin, Bussolati and Pearse (1967) found no calcitonin in the regular colloid-producing follicular cells of hog and dog thyroid. However, high concentrations were present in the scattered “parafollicular” or C cells. These
were originally described by Baber ( 1876) and lated by Nonidez ( 1932).
They were shown by Godwin (1937) and Pearse and Carvalheira
(1967) to be of ultimobranchial origin. Final c o d h a t i o n of the ultimobranchial origin of calcitonin came when high concentrations of the hormone were demonstrated in the ultimobranchial glands of chickens (Copp
et al., 1967a; Tauber, 1967) and the dogfish shark (Copp et al., 196%).
No hypocalcemic activity could be demonstrated in extracts of the thyroid
glands in these species.
B, Assay
The standard bioassay procedures depend on the hypocalcemic effect
of the hormone in young rats, as measured by the fall in plasma calcium
after 50-60 min (Hirsch et al., 1964; Kumar et al., 1965; Cooper et al.,
196-I). Copp and Kuczerpa ( 1968) used the time-integrated hypocalcemic
response and found that the sensitivity to hormone decreased rapidly with
increasing age. The response in 9-month-old rats was only 5% of that in
4-week-old weanlings.
With the availability of pure porcine calcitonin, very sensitive radioimmunoassays have been developed which measure the hormone in the
range of 0.01-0.1 ng (Deftos et al., 1968; Arnaud et al., 1968).
387
zation and the Adopted Names Council of the American Medical
Association.
A. History
The history of the calcitonin field was reviewed recently by Copp
(1967). The hormone was discovered in 1961 (Copp et al., 1961, 1962)
when it was shown that high calcium perfusion of the thyroid-parathyroid
gland complex in the dog released a potent hypocalcemic factor. This
work was subsequently confirmed by Kumar et al. (1963). The name
“calcitonin” was proposed for the hormone because it was apparently involved in regulating the tone of calcium in body fluids. Although the hormone was originally thought to come from the parathyroids, Hirsch et al.
(1963) showed that a potent hypocalcemic substance could be extracted
from rat thyroid. They tentatively proposed the alternative name “thyrocalcitonin” to indicate the gland of origin and the possible identity with
calcitonin. In immunofluorescent studies with antibodies to porcine calcitonin, Bussolati and Pearse (1967) found no calcitonin in the regular colloid-producing follicular cells of hog and dog thyroid. However, high concentrations were present in the scattered “parafollicular” or C cells. These
were originally described by Baber ( 1876) and lated by Nonidez ( 1932).
They were shown by Godwin (1937) and Pearse and Carvalheira
(1967) to be of ultimobranchial origin. Final c o d h a t i o n of the ultimobranchial origin of calcitonin came when high concentrations of the hormone were demonstrated in the ultimobranchial glands of chickens (Copp
et al., 1967a; Tauber, 1967) and the dogfish shark (Copp et al., 196%).
No hypocalcemic activity could be demonstrated in extracts of the thyroid
glands in these species.
B, Assay
The standard bioassay procedures depend on the hypocalcemic effect
of the hormone in young rats, as measured by the fall in plasma calcium
after 50-60 min (Hirsch et al., 1964; Kumar et al., 1965; Cooper et al.,
196-I). Copp and Kuczerpa ( 1968) used the time-integrated hypocalcemic
response and found that the sensitivity to hormone decreased rapidly with
increasing age. The response in 9-month-old rats was only 5% of that in
4-week-old weanlings.
With the availability of pure porcine calcitonin, very sensitive radioimmunoassays have been developed which measure the hormone in the
range of 0.01-0.1 ng (Deftos et al., 1968; Arnaud et al., 1968).