Stimulatory effects of short-term calcitonin administration on plasma calcium, magnesium, phosphate, and glucose in juvenile Siberian sturgeon Acipenser baerii.

Calcitonin (CT) has a potential function in calcium (Ca) regulation, but there are conflicting observations in fishes. Because of the lack of calcified endoskeleton, sturgeons have low Ca circulating compared with teleost fish and the function of CT on Ca in sturgeon is very less understood. The purpose of this study was to investigate the impact of injection of salmon CT on plasma Ca, magnesium (Mg), phosphate (PHO), and glucose levels of juvenile Siberian sturgeon Acipenser baerii. Sixteen-month-old fish (429.6 ± 12.1 g) were intraperitoneally injected with a single dose of CT (5 μg kg-1 BW) and saline solution as a control group. Thereafter, blood sampling was performed at 0, 1, 2, 4, 6, 12, 24, and 48 h after injection. CT produced marked increases in all variables measured. The highest levels of Ca (6.77 ± 0.53 mg dL-1), Mg (9.79 ± 0.16 mg dL-1) and PHO (1.74 ± 0.05 mg dL-1) were recorded at 2 h after CT injection and showed significant difference compared with control treatment (Ca 4.75 ± 0.12 mg dL-1; Mg 5.47 ± 0.16 mg dL-1 and PHO 1.23 ± 0.06 mg dL-1). It also likely produced hyperglycemia. However, the differences with the controls were not statistically significant, possibly due to interference with the hyperglycemia induced by the stress of injection. Our results showed that the injection of 5 μg kg-1 BW CT to Siberian sturgeon has an incremental effect on plasma Ca, Mg, and PHO. The increase in plasma Ca level indicated that CT has a potent hypercalcemic effect in sturgeon under laboratory condition, in contrast to the hypocalcemic effects reported for teleosts.