Effects of salmon calcitonin on calcium deposition on and release from calcified tissues in fed and starved goldfish Carassius auratus

Abstract

Effects of salmon calcitonin on calcium physiology of the otolith, rib bone, pharyngeal bone, and scale were examined in fed and starved goldfish Carassius auratus. Fish were intraperitoneally given salmon calcitonin at a dose of 10 ng/g body weight four times every other day. They were then incubated in ⁴⁵Ca-containing water for 24 h to examine the effect of the hormone on calcium deposition on these tissues. Another group of goldfish was incubated in ⁴⁵Ca-bone water for 2 days to prelabel the tissues with ⁴⁵Ca. Then they were kept in ⁴⁵Ca-free water for 8 days, during which they were given calcitonin four times every other day. The effect of calcitonin on calcium release from the tissues was examined by analyzing the prelabeled radioactivity. Calcitonin had no effect on plasma calcium concentrations or on calcium deposition in any of the tissues in fed fish. In starved fish, however, calcitonin increased calcium deposition on the rib bone, pharyngeal bone, and scale. In the starved fish, plasma calcium levels were not affected by the hormone, but plasma ⁴⁵Ca activity was lower in the calcitonin-treated group than in the control group. Calcitonin had no effect on calcium release from the bone and the scale, but reduced radioactivity in the otoliths of fed fish. These results suggest that calcitonin functions as an accelerator for calcium deposition on the bone and the scale in starved goldfish.