Annual correlative changes in some biochemical contents of seminal vesicleand testis in the catfish Clarias batrachus (L)

The seminal vesicle (SV) and testis of Clarias batrachus (L) exhibit signif icant annual variations in SVSI and GSI, and in the levels of total protein s, fructose, hexosamines and sialic acid with low values in resting phase a nd high levels in spawning phase. Histologically, the SV is composed of num erous lobules lined by epithelial cells enclosing a lumen and an interstiti al matrix containing interstitial cells (homologous to Leydig cells) and fi broblasts. In the preparatory phase, the SV undergoes extensive growth and proliferation of the lobules (April) with numerous buds of differentiating lobules. With the progress of secretory activity, the epithelial cells whic h were tall and columnar initially become cubical and squamous. The secreti ons filled the lumen resulting in distension and enlargement of the follicl es and spermatozoa appear in the lumina. After voiding the contents, the SV lobules collapse and degenerate. New lobules are formed from the interstit ium by proliferation. They showed transient secretory activity and remained inactive during the resting phase. The increases in total proteins, fructo se, hexosamines and sialic acid levels in the SV are directly correlated wi th the histological changes and secretory activity. The levels of phospholi pids and free fatty acids which showed significant variations are low durin g the spawning phase. The decline in the concentrations of esterified and f ree cholesterol (EC and FC) in both the testis and SV during the breeding s eason suggests their utilization as precursors in the synthesis of steroid hormones. The two, however, maintained an inverse relation during the non-b reeding season with EC levels high and FC levels low. Scattered spermatogen ic cysts in different stages of development are present in the SV epitheliu m. The similarities in the annual distribution of various biochemical corre lates, and the presence of interstitial (Leydig) cells and scattered sperma togenic cysts suggest that the SV has a common origin with the testis and i s specialized for secreting a glyco-lipoprotein-rich substance for temporar y storage of the sperm.