Different secretory actions of pancreastatin in bovine and human parathyroid cells |
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Authors: | P Ridefelt P Hellman M Stridsberg G Åkerström J Rastad |
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Institution: | (1) Department of Surgery, University Hospital, S-751 85 Uppsala, Sweden;(2) Department of Clinical Chemistry, University Hospital, S-751 85 Uppsala, Sweden |
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Abstract: | Chromogranin A is an acidic protein that is costored and cosecreted with parathyroid hormone (PTH) from parathyroid cells. Pancreastatin (PST), is derived from chromogranin A, and inhibits secretion from several endocrine/neuroendocrine tissues. Effects of different pancreastatin peptides were investigated on dispersed cells from bovine and human parathyroid glands. Bovine PST(1–47) and bovine PST(32–47) inhibited PTH release from bovine cells in a dose-dependent manner. The former peptide was more potent and suppressed the secretion at 1–100 nM. This inhibition was evident in 0.5 and 1.25 mM, but not in 3.0 mM external Ca2+. Both peptides failed to alter the concentration of cytoplasmic Ca2+(Ca2+]i) of bovine cells. Human PST(1–52) and PST(34–52) did not affect PTH release or Ca2+]i of parathyroid cells from patients with hyperparathyroidism, nor Ca2+]i of normal human parathyroid cells. Furthermore, bovine PST(1–47) and bovine PST(32–47) failed to alter the secretion of abnormal human parathyroid cells. The study indicates that PST exerts secretory inhibition on bovine but not human parathyroid cells, and that this action does not involve alterations of Ca2+]i. |
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Keywords: | parathyroid glands parathyroid hormones calcium chromogranins hyperparathyroidism |
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