Calcitonin primarily works by regulating the skeletal system, kidneys, and gastrointestinal tract, lowering blood calcium levels and improving or alleviating bone pain caused by osteoporosis.
1. Effects on bones: Calcitonin inhibits bone autolysis and resorption, reducing calcium release from bones; simultaneously, bones continuously absorb calcium from the blood, lowering blood calcium levels. It also inhibits bone salt dissolution and transfer, inhibits bone resorption, increases bone turnover, and increases urinary excretion of calcium and phosphorus, thus lowering blood calcium and phosphorus levels. For patients with osteoporosis, this product can reduce continued bone loss and decrease the incidence of fractures.
2. Inhibits the release of pain mediators, blocks their receptors, and increases β-endorphin release, resulting in peripheral and central analgesic effects.
3. Effects on the kidneys: By inhibiting the reabsorption of calcium, phosphorus, and sodium by the renal tubules, it increases their excretion in urine, but does not lower blood calcium levels below the normal range, and has minimal effect on potassium and hydrogen ions. 4. Effects on the gastrointestinal tract: It can inhibit intestinal calcium transport and suppress the secretion of gastric acid, gastrin, and insulin. Clinically, calcitonin can be used to treat osteitis deformans, osteoporosis in the elderly, and hypercalcemia caused by bone metastases.
Calcitonin eel is a peptide hormone that lowers calcium concentration in the blood. In humans, it is released by thyroid cells and acts to decrease the formation and absorptive activity of osteoclasts. Its role in regulating plasma calcium is much greater in children and in certain diseases than in normal adults. Calcitonin, eel is the thyroid hormone peptide that contributes to the regulation of calcium homeostasis, widely used in the research of postmenopausal osteoporosis.
Calcitonin is hypocalcemic hormone produced by the parafollicular C cells of the thyroid or by the ultimobranchial bodies of nonmammalian vertebrates. Calcitonin decreases blood calcium and phosphate due to inhibition of resorption by osteoblasts and osteocytes.
A method for the preparation of calcitonin eel acetate, comprising the steps of: deprotecting a RinkAmideMBHA resin with a deprotecting reagent to remove the Fmoc protecting group; using the deprotected RinkAmideMBHA resin as a starting material, and using the Fmoc-protected amino acid as a monomer, coupling amino acids in sequence to obtain a calcitonin eel acetate peptide resin; wherein the coupling of amino acids at positions 1, 2, 4-13, 15-19, 21, 23, 25 and 27-32 amino acids were N,N-diisopropylcarbodiimide (DIC)/1-hydroxybenzotriazole (HOBt); the condenser for coupling amino acids 3, 14, 20, 22, 24 and 26 is benzotriazol-1-yl-oxytripyrrolidinium hexafluorophosphate (PyBOP)/HOBt; prior to coupling amino acids 2 to 32, the amino acids in the 2nd to 32nd positions were removed with the Before coupling amino acids in positions 2 to 32, the Fmoc protecting group of the previous coupling product was sequentially removed with said deprotecting reagent; cleavage of said calcitonin eel acetate peptide resin, followed by addition of ether to precipitate said calcitonin eel acetate peptide resin to obtain reduced calcitonin eel acetate crude peptide; cyclization of said reduced calcitonin eel acetate crude peptide to obtain oxidized calcitonin eel acetate crude peptide; and purification, transsalting, concentration, and lyophilization of said oxidized calcitonin eel acetate crude peptide to obtain calcitonin eel acetate.
Calcitonin, eel effectively induces a concentration-dependent stimulation of phosphoinositide hydrolysis and stimulates prolactin release compared to salmon calcitonin in cultured anterior pituitary cells.
Calcitonin, eel is inactive on the inhibition of prolactin release under thyrotropin releasing hormone (TRH) stimulated conditions.
Structure and conformation
Eel calcitonin has structural similarities with salmon calcitonin and, to date, research preparations have been evaluated with reference to the salmon calcitonin standard using the rat hypocalcaemia assay method. However, as salmon and eel calcitonins do have structural differences, which are likely to become evident if different in vivo or in vitro assay methods are used, a standard for eel calcitonin is required.
