Verbost P M, Fenwick J C
Department of Animal Physiology, University of Nijmegen, The Netherlands.
Gen Comp Endocrinol. 1995 May;98(2):185-92. doi: 10.1006/gcen.1995.1059.
The effects of an N-terminal, a C-terminal, and a mid-fragment of stanniocalcin, the primary hypocalcemic hormone in fish, on plasma total and free (ionic) calcium levels and whole animal calcium influx were tested in eels. Both the N- and the C-terminal fragments were hypocalcemic, causing 18 and 12% reduction in plasma calcium in stanniectomized eels, respectively. With both fragments the hypocalcemic action is transient. The hypocalcemia caused by the C-terminal fragment, although more rapid, is not as pronounced as the hypocalcemic action of the N-terminal fragment. Only the C-terminal fragment reduced calcium influx. The hypocalcemic activity of the C-terminal fragment then can be explained by its effect on calcium influx. The N-terminal fragment appears to function in a different manner. The mid-fragment has no effect on plasma calcium or calcium influx. The different parts of the hormone are concluded to have different effects.
