Histamine content of the digestive tract of a catfish Clarias batrachus (Linn.) in relation to spawning, sex and seasonal variation.

ABSTRACT

Histamine content of the digestive tract of a catfish Clarias batrachus has been estimated biologically on the atropinized guineapig ileum. A significant decrease of histamine content has been observed with the decrease of gonosomatic index (G.S.I.) during breeding season in female fishes, while no such type of change in histamine content of male fishes during breeding season has been noted. In the summer histamine content of both the sexes was signivicantly lowered in comparison with the histamine content during breeding season in both the sexes. It is concluded that higher histamine content in prespawing female fishes during breeding season may be due to the inhibition of the enzyme histaminase by gonadotrophines. It is also suggested that the route of inactivation of histamine during breeding season may be different in both the sexes, while in summer a common factor may be involved in depletion of histamine content of both the sexes.