Fujimi T, Baba H, Fukase M, Fujita T. Direct inhibitory effect of amino-terminal parathyroid hormone fragment [PTH(1-34)] on PTH secretion from bovine parathyroid primary cultured cells in vitro.
Biochem Biophys Res Commun 1991;
178:953-8. [PMID:
1872875 DOI:
10.1016/0006-291x(91)90984-f]
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Abstract
We have examined the possibility of direct inhibitory effect of PTH(1-34) on PTH secretion in bovine parathyroid cells. As low as 10(-12) M PTH(1-34) completely inhibited low calcium (0.5 mM Ca2+)-stimulated PTH secretion by these cells. In the presence of 1.25 mM Ca2+, 10(-12) M PTH(1-34) inhibited PTH secretion by about 14.3% of the basal value, while 10(-11) M or higher concentration of PTH(1-34) showed potent inhibitory effects equivalent to the inhibitory action of high calcium concentration (2.5 mM Ca2+) on PTH secretion. At 2.5 mM Ca2+, as much as 10(-9) M PTH(1-34) failed to inhibit PTH secretion further. These results suggest that PTH(1-34) might directly, not via calcium concentration, inhibit PTH secretion by parathyroid cells and that a cooperative mechanism could exist between calcium and PTH(1-34) to inhibit PTH secretion.
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