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Effect of cadmium on prolactin cell activity and plasma electrolytes in the freshwater teleost Oreochromis mossambicus

1989; Elsevier BV; Volume: 14; Issue: 4 Linguagem: Inglês

10.1016/0166-445x(89)90028-3

1879-1514

Hua Fu, R.A.C. Lock, S.E. Wendelaar Bonga,

Reproductive biology and impacts on aquatic species

Exposure of tilapia to a sublethal cadmium (Cd) concentration (10 μg Cd/l) led after 4 days to a rapid and substantial decrease of plasma total Ca and a small drop in plasma osmolarity and Na+. This ionic disturbance was only transitory and control levels were reached after 14 days. Prolactin is implicated in this recovery since prolactin cell activity increased markedly during the first 4 days. The gradually decreasing activity of prolactin cells thereafter points to induction of a second mechanism sustaining the resistance of fish to Cd. In spite of the pronounced hypocalcemia, no apparent signs of demineralisation of bony tissues were observed. Since administration of prolactin to tilapia is known to exert a hypercalcemic action by increasing the net branchial Ca2+-uptake, it is concluded that restoration of Cd-induced hypocalcemia is connected with the observed stimulation of prolactin cell activity.