Annual testicular cycles and correlatory histochemical changes exhibited by the nucleus lateralis tuberis (NLT) in the Indian catfish, Clarias batrachus (linn.).

The seasonal changes observed in the neurons of the nucleus lateralis tuberis (NLT) of Clarias batrachus have been studied with particular reference to the testicular cycle throughout the year at 15 days interval. The neurons of the pars medialis (pm) and pars ventrocaudalis (pvc) subgroups of the four NLT components exhibited steady enlargements and degranulation, consistent with the spermatocyte enlargement. During spermiation phase (August), when the fishes spermiated, the neurons of pm and pvc attained their maximum size. Thus, a possible link existing between the hypothalamic nucleus (pm and pvc) and the testicular activity has been established.