Abstract

MECHANISM OF PESTICIDE INDUCTION ON PITUICYTES OF FRESH WATER GOBIID FISH GLOSSOGOBIUS GIURIS

Narayanaswamy. S.Y*

ABSTRACT

Histopathology on the Hypophysis of fish Glossogobius giuris was observed during spawning phase, on the treatment with sublethal concentrations of Malathion (0.05, 0.25 and 0.5 ppm) for 24, 48, 72 and 96 hrs intervals. Investigation on Hypophysis includes PRL and GTH cells showed degranulation and hypertrophy of cells and nuclei, after the fishes were exposed to Malathion treatment, appearance of extensive intercellular spaces. In higher concentration of malathion with 0.5 ppm for 24 hrs, the cells showed various stages of degranulation which were distributed sparsely. A reduction in the number and diameter of the pituicytes, which indicates possible reduction in the synthesis of hormones. In 24-96 hrs treated fish prolactin cells showed degranulation and vacuolization in the cytoplasm and conspicous intercellular spaces. These cellular disturbances in the RPD may be directly related to the increase in concentration of malathion. This suggests an acute stress response, since prolactin is known to be released under stress condition. The results indicate that, malathion is capable of inhibiting development of pituicytes. A low dose of malathion brings about a significant reduction in reduction in the release of gonadotrophins. A higher concentration of malathion reduces gonadotrophs in the PPD, implying a possible reduction both in the synthesis and release of gonadotropins.

Keywords: Malathion, G.giuris, PRL, GTH and Hypophysis.