Effect of two pesticides on ovarian 32P uptake and gonadotrophin concentration during different phases of annual reproductive cycle in the freshwater catfish, Heteropneustes fossilis (Bloch)

Abstract

Ovarian 32P uptake and gonadotrophic contents of the pituitary gland and blood serum after 4 weeks of treatment with Cythion and Hexadrin at safe or sublethal concentrations were measured in Heteropneustes fossilis during five different phases of the annual reproductive cycle. Gradual reduction in the ovarian 32P uptake as well as in gonadotrophin level started from the preparatory phase and was more pronounced and significant during prespawning and spawning phases. In early postspawning period the changes in ovarian 32P uptake and gonadotrophin content were less than those observed in the previous two phases after Cythion treatment but similar to those observed after Hexadrin administration. Values in the late postspawning period were similar to those observed in preparatory phase. These pesticides seem to interfere with gonadotrophin secretion and their action on ovary with resultant decrease in ovarian activity during all phases of the annual reproductive cycle in H. fossilis.