摘要：Mastacembelus armatus (Lacepede) is a seasonal breeder with a single breeding peak in a year which extends from late July to September. Plasma calcium and stanniocalcin levels were determined throughout the reproductive cycle. The level of both plasma calcium and stanniocalcin increases during advanced maturation phase with simultaneous increses in gonadosomatic index reaching the peak during spawning phase. It gradually decreases after spawning and significantly reduced during postspawning and resting phase. Histochemical analysis also indicates the seasonal variation in the activity of the gland, corpuscles of Stannius (CS) with respect to the reproductive cycle. CS exhibit signs of hyperactivity during prespawning and spawning phase however its reduced activity during post spawning phase and almost inactivity were noted during spent phase. 17-β estradiol administration for 10 days also induced hypercalcemia in female M. armatus fed with calcium deficient food. An increased level of stanniocalcin in 17-β estradiol treated fish reflects the hyperactivity of CS. Therefore it can be concluded that hyperactivity of CS is due to elevated calcium level through extra intestinal routes that accompanied ovarian maturation. Stanniocalcin from hyperactive CS reduces the increasing level of plasma calcium in the fish.
关键词：mastacembelus armatus (lacepede);reproductive cycle;corpuscles of stannius;plasma calcium;stanniocalcin;17-β estradiol
