Carbofuran induced impairment in the hypothalamo-neurohypophyseal-gonadal complex in the teleost, Channa punctatus (Bloch).

The effect of chronic exposure to carbofuran (4.5 ppm in static water) for six months on the gonadal histophysiology and hypothalamo-neurohypophyseal complex was studied in Channa punctatus. Experimental observations revealed significant inhibition of gonadal development with associated degenerative abnormalities as evidenced by ovarian and testicular histology and reduced gonadosomatic index. Degenerative changes in ovary were exihibited by stag e I (oogonium) and stage II (immature/non-vitellogenic) oocytes as marked b y perinuclear ooplasmic lysis, clumping and dissolution resulting in disint igration of nuclear material altogether attributed to complete degeneration of such oocytes. Testicular deleterious changes included degeneration of s permatogenic elements and necrosis of interstitial cells of Leydig. Correla tive histophysiological changes were also observed in the pituitary gonadot rophs and hypothalamic, nucleus pre-opticus, neurons that were smaller, ina ctive and less in number with associated necrosis. Corresponding to the cha nges in nucleus pre-opticus neurons, significant inhibition of brain monoam ine oxidase enzyme activity was also re: corded in treated group. These obs ervations suggest that carbofuran even at low concentration level tinder lo ng-term exposure is capable of inducing retardation of gonadal development which might have been mediated through the impairment of the hypotlialamone uroliypophyseal-gonadal axis in this species.