Histological alterations in the prolactin cells of a teleost, Heteropneustes fossilis, after exposure to cypermethrin

Freshwater fish Heteropneustes fossilis (H. fossilis) were subjected to 5.76 μg/L (80% of 96 h LC₅₀) and 1.44 μg/L (20% of 96 h LC₅₀) of cypermethrin for short-term (96 h) and long-term (28 days) duration, respectively. Plasma calcium of H. fossilis exposed for short term (96 h) to cypermethrin exhibited no change at 24 h. The levels indicate a decrease in plasma calcium at 48 h. This response persists till the close of experiment (96 h). No change has been noticed throughout the experiment in the histological structure and nuclear volume of prolactin cells of short-term cypermethrin treated fish. Long-term exposure of cypermethrin to fish provoked hypocalcemia. The prolactin cells remain unchanged till 7 days following cypermethrin treatment. After 14 days, the nuclear volume exhibits an increase and the cells exhibit degranulation. These changes increase progressively 21 days onwards. Also, few degenerating cells are discerned after 28 days.