Effects of stanniectomy and experimental hypercalcemia on plasma calcium levels and calcium influx in American eels, Anguilla rostrata, LeSueur

Intraperitoneal injection of CaCl 2 in intact, sham-stanniectomized, and stanniectomized American eels, Anguilla rostrata (LeSueur), resulted in a rapid elevation of plasma calcium level which was more marked and of longer duration in the stanniectomized eels. The same treatment reduced whole body calcium influx ( J inCa 2+) in the intact and shamstanniectomized groups for the first but not the second of two 4 hr flux periods. The same treatment did not affect J inCa 2+ in the stanniectomized eels. We conclude that calcium loading in eels with intact stannius corpuscles (CS) results in the release of a CS hormone (stanniocalcin) which inhibits the uptake of calcium from the environment and that this facilitates the return to normocalcemia. These data provide direct evidence for a relationship between stanniocalcin release in vivo and a hypocalcemic response and the first evidence concerning the functional turnover time of this hormone.