STUDY ON THE EFFECTS OF ESTRADIOL-17-BETA, ESTRONE, CATECHOL ESTROGENS, [D-ALA(6)]-LUTEINIZING HORMONE-RELEASING HORMONE AND HUMAN CHORIONIC-GONADOTROPIN ON SERUM LEVELS OF LIPIDS AND VITELLOGENIN IN THE IMMATURE DUCKLING (ANAS-PLATYRHYNCHOS)

1. The effects of administration of estradiol-17beta (E2), estrone (E1 ), catechol estrogens, [D-Ala6]-luteinizing hormone releasing hormone (LHRH) and human chorionic gonadotropin (HCG) on serum levels of vitel logenin and lipids were examined in immature ducklings. 2. E2 brought about an elevation in serum levels of total lipid, triglyceride, chole sterol and vitellogenin. 3. Treatment with both LHRH and E2 resulted i n an increase in serum levels or total lipid, triglyceride, cholestero l and vitellogenin. 4. Treatment with LHRH alone, HCG, E1 or catechol estrogen failed to exert any effect on serum lipid or vitellogenin lev el. 5. The results indicate that, of the various hormones examined inc luding estrogens, LHRH and HCG, only E2 was able to affect serum lipid and vitellogenin concentrations in the duckling.