Uses of calcitonin
Treatments
Calcitonin can be used therapeutically for the treatment of hypercalcemia or osteoporosis. In a recent clinical study, subcutaneous injections of calcitonin have reduced the incidence of fractures and reduced the decrease in bone mass in women with type 2 diabetes complicated with osteoporosis.Subcutaneous injections of calcitonin in patients with mania resulted in significant decreases in irritability, euphoria and hyperactivity and hence calcitonin holds promise for treating bipolar disorder. However no further work on this potential application of calcitonin has been reported. Diagnostics
It may be used diagnostically as a tumor marker for medullary thyroid cancer, in which high calcitonin levels may be present and elevated levels after surgery may indicate recurrence. It may even be used on biopsy samples from suspicious lesions (e.g., lymph nodes that are swollen) to establish whether they are metastases of the original cancer. Cutoffs for calcitonin to distinguish cases with medullary thyroid cancer have been suggested to be as follows, with a higher value increasing the suspicion of medullary thyroid cancer:
females: 5 ng/L or pg/mL
males: 12 ng/L or pg/mL
children under 6 months of age: 40 ng/L or pg/mL
children between 6 months and 3 years of age: 15 ng/L or pg/mLWhen over 3 years of age, adult cutoffs may be used
Increased levels of calcitonin have also been reported for various other conditions. They include: C-cell hyperplasia, nonthyroidal oat cell carcinoma, nonthyroidal carcinoma and other nonthyroidal malignancies, acute kidney injury and chronic kidney failure, hypercalcemia, hypergastrinemia, and other gastrointestinal disorders, and pulmonary disease.
Calcitonin has short absorption and elimination half-lives of 10–15 minutes and 50–80 minutes, respectively. Salmon calcitonin is primarily and almost exclusively degraded in the kidneys, forming pharmacologically inactive fragments of the molecule. Therefore, the metabolic clearance is much lower in patients with end-stage kidney failure than in healthy subjects. However, the clinical relevance of this finding is not known. Plasma protein binding is 30% to 40%. Characteristics in patients
There is a relationship between the subcutaneous dose of calcitonin and peak plasma concentrations. Following parenteral administration of 100 IU calcitonin, peak plasma concentration lies between about 200 and 400 pg/ml. Higher blood levels may be associated with increased incidence of nausea, vomiting, and secretory diarrhea. Preclinical safety data
Conventional long-term toxicity, reproduction, mutagenicity, and carcinogenicity studies have been performed in laboratory animals. Salmon calcitonin is devoid of embryotoxic, teratogenic, and mutagenic potential. An increased incidence of pituitary adenomas has been reported in rats given synthetic salmon calcitonin for 1 year. This is considered a species-specific effect and of no clinical relevance. Salmon calcitonin does not cross the placental barrier. In lactating animals given calcitonin, suppression of milk production has been observed. Calcitonin is secreted into the milk. Pharmaceutical manufacture
Calcitonin was extracted from the ultimobranchial glands (thyroid-like glands) of fish, particularly salmon. Salmon calcitonin resembles human calcitonin, but is more active. At present, it is produced either by recombinant DNA technology or by chemical peptide synthesis. The pharmacological properties of the synthetic and recombinant peptides have been demonstrated to be qualitatively and quantitatively equivalent.