Annual cyclic variations in some biochemical constituents of seminal vesicle and testis of the catfish Heteropneustes fossilis (bloch): A study correlating plasma testosterone level

In Heteropneustes fossilis. significant annual variations were observed in seminal vesicle-somatic index (SVSI), gonadosomatic index (GSI), concentrat ions of total proteins, hexosamines, fructose and glucose in both SV and te stis, and in plasma testosterone with high values in late prespawning-early spawning phases (June-July) and low or undetectable levels in resting phas e (December-January) except for glucose. There is an inverse relationship b etween the annual patterns of fructose and glucose with fructose dominant i n the prespawning and early spawning phases (June-July), and glucose in the resting phase (November-January), The increase in the concentrations of SV and testicular protein, hexosamine and fructose can be correlated with the increase in testosterone concentration on one hand and with the increase o f SVSI and GSI, on the other. The decrease in glucose level in the recrudes cent phase may be due to its increased conversion into fructose, the main s eminal sugar in this species.