Download Calcitonin

<BioChemistry>
Calcitonin
2006312182
김준희
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Introduction
Calcitonin is a 32-amino acid polypeptide hormone that is
produced in humans primarily by the parafollicular (also
known as C-cells) of the thyroid, and in many other
animals in the ultimobranchia body. It acts to reduce blood
calcium (Ca2+), opposing the effects of parathyroid
hormone(PTH).
It has been found in fish, reptiles, birds, and mammals. Its
importance in humans has not been as well established as
its importance in other animals.
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Feature
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Biosynthesis
Calcitonin is formed by the proteolytic cleavage of a larger
prepropeptide, which is the product of the CALC1 gene
(CALCA). The CALC1 gene belongs to a superfamily of
related protein hormone precursors including islet amyloid
precursor protein, calcitonin gene-related peptide, and the
precursor of adrenomedullin.
The calcitonin receptor, found primarily on osteoclasts,
is a G protein-coupled receptor, which is coupled by Gs
to adenylyl cyclase and thereby to the generation of
cAMP in target cells.
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Physiology
The hormone participates in calcium(Ca2+) and
phosphorus metabolism. In many ways, calcitonin has the
counter effects of parathyroid hormone(PTH).
To be specific, reduces blood Ca2+ levels in three ways:
1) Decreasing Ca2+ absorption by the intestines.
2) Decreasing osteoclast activity in bones.
3) Decreasing Ca2+ and phosphate reabsorption by the
kidney tubules.
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Action
1) Bone mineral metabolism:
- Prevent postprandial hypercalcemia resulting from
absorption of Ca2+ from foods during a meal - Promote
mineralization of skeletal bone.
- Protect against Ca2+ loss from skeleton during periods
of Ca2+ stress such as pregnancy and lactation.
2) Vitamin D regulation
3) A satiety hormone:
- Inhibit food intake in rats and monkeys - May have CNS
action involving the regulation of feeding and appetite.
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Sequence
Protein:
1vllaalvqdy | vqmkaseleq | eqeregssld | sprskrcgnl | stcmlgtytq
51 dfnkfhtfpq | taigvgapgk | krdmssdler | dhrphvsmpq | nan
Gene sequence:
1 gtcctgctgg | ctgcactggt | gcaggactat | gtgcagatga | aggccagtga |
51 gctggagcag | gagcaagaga | gagagggctc | cagcctggac | agccccagat |
101 ctaagcggtg | cggtaatctg | agtacttgca | tgctgggcac | atacacgcag |
151 gacttcaaca | agtttcacac | gttcccccaa | actgcaattg | gggttggagc |
201 acctggaaag | aaaagggata | tgtccagcga | cttggagaga | gaccatcgcc |
251 ctcatgttag | catgccccag | aatgccaact | aa
- Calcitonin and Calcitonin gene related peptide are transcribed from
the same gene; differential splicing after transcription yields the
different mRNAs for calcitonin and calcitonin gene related peptide.
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Further Information
Orthologs
Human
Mouse
Entrez
796
12310
Ensembl
ENSG00000110680
ENSMUSG00000030669
Uniprot
P01258
Q99JA0
Refseq
NM_001033952 (mRNA)
NP_001029124 (protein)
NM_001033954 (mRNA)
NP_001029126 (protein)
Location Chr 11: 14.94 - 14.95 Mb
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Chr 7: 114.42 - 114.43 Mb
Reference
1. http://www.pubmed.gov
2. http://www.wikipedia.org
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