SYNTHESIS AND RELEASE OF PHOSPHOPROTEIN AND PHOSPHOLIPID IN THE FEMALE FRESH-WATER CATFISH, HETEROPNEUSTES-FOSSILIS IN RESPONSE TO ESTRADIOL-17-BETA DURING 2 DIFFERENT PHASES OF ANNUAL REPRODUCTIVE-CYCLE

Changes in phosphoprotein and phospholipid of the liver and serum were observed in response to the administration of different doses of estradiol-17-beta during postspawning and preparatory phases of the reproductive cycle of Heteropneustes fossils. All tested doses of estradiol-17-beta (5-mu-g, 10-mu-g, and 50-mu-g/fish for 7 days) increased liver RNA without altering DNA content in both postspawning and preparatory phases, only medium (10-mu-g/fish) and high (50-mu-g/fish) doses during the postspawning phase, and all three doses (5-mu-g, 10-mu-g and 50-mu-g) during the preparatory phase heightened phospholipid and phosphoprotein levels in both the liver and serum. Treatment with estradiol-17-beta during both reproductive phases at doses of 10 and 50-mu-g/fish resulted in increased liver protein. The influences of estrogen treatment on phospholipid synthesis varied slightly according to individual phases of the reproductive cycle. Low doses of estradiol-17-beta (5-mu-g/fish) induced the synthesis of lipids other than phospholipid in the liver during the postspawning season. On the other hand, medium (10-mu-g/fish) and high (50-mu-g/fish) doses of the same hormone triggered the synthesis of phospholipid without affecting total lipid concentrations in the liver during preparatory phase.