Annual cyclical changes in the monoamine oxidase (MAO) activity in the testis of the teleost, Channa punctatus (Bloch)

Correlative changes in the monoamine oxidase (MAO) activity were recorded biochemically in the testis of Channa punctatus during different phases of the annual reproductive cycle. MAO activity increased with increase in testicular weight and maturity and declined during the postspawning and resting phases. This suggests that MAO may play some role in the growth cycle of the testis. On the other hand, 5-hydroxytryptamine (5-HT) concentration was found to be high in the testis during the resting phase and was markedly reduced during the spawning phase. Thus, there seems to be an inverse relationship between MAO and 5-HT in the testis during its annual cycle.