Changes in gonadotrophin, lipid and cholesterol levels during annual reproductive cycle in the freshwater teleost, Cirrhinus mrigala (Ham.).

Pituitary gonadotrophin started increasing with gonadosomatic index from preparatory phase but increase in serum gonadotrophin became evident from prespawning phase. However, their peaks were noticed in spawning phase. During other phases of reproductive cycle their values were low except for female pituitary gonadotrophin potency which remained comparatively high during postspawning phase. An increase in ovarian and decrease in testicular lipid started from preparatory phase which continued till spawning phase. Liver lipid in either sex decreased during prespawning and spawning phases. Lipid level was low in ovary but was high in testis and liver during the remaining period of the year. Liver cholesterol was low during spawning and high in prespawning phase whereas serum cholesterol was low during prespawning and spawning phases and remained high during other and peak was recorded during spawning phase. Testicular cholesterol was low during preparatory and postspawning phases and high during the rest of the period of reproductive cycle.