Open AccessEffect of Luteinising Hormone‐Releasing Hormone Analogue and Human Chorionic Gonadotropin on Ovulation, Plasma and Ovarian Levels of Gonadal Steroids in Greenback Flounder Rhombosolea tapirina
Author(s) -
Poortenaar Carolyn W.,
Pankhurst Ned W.
Publication year - 2000
Publication title -
journal of the world aquaculture society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.655
H-Index - 60
eISSN - 1749-7345
pISSN - 0893-8849
DOI - 10.1111/j.1749-7345.2000.tb00351.x
Subject(s) - medicine , human chorionic gonadotropin , endocrinology , ovulation , biology , gonadotropin , flounder , hormone , testosterone (patch) , oocyte , ovary , fish <actinopterygii> , fishery , embryo
Female greenback flounder Rhombosolea tapirina were treated with either des Gly 10 [D‐Ala 6 ] LHRH ethylamide (LHRH‐a) at 50 or 100 pg/kg intraperitoneal injection (ipi), LHRH‐a cholesterol pellet (LHRH‐a pellet) 100 μg/kg implanted intraperitoneally, or human chorionic gonadotropin (hCG) 1,000 IU/kg ipi. Treatment with hCG, LHRH‐a (50 μg/kg) ipi and LHRH‐a pellet increased the total number of ovulations above control levels. LHRH‐a (100 μg/kg) ipi was not consistently more effective than the control and both LHRH‐a (50 μg/kg) ipi and LHRH‐a pellet induced more ovulations than LHRH‐a (100 μg/kg) ipi. Of those fish that ovulated, most ovulated more than twice, and most ovulations occurred at daily intervals. Oocyte diameters increased and oocyte stage advanced significantly in response to all exogenous hormone treatments. This was accompanied by increases in plasma and ovarian levels of 17β‐estradiol (E 2 , and in most cases, plasma and ovarian levels of testosterone (T). Plasma and ovarian levels of 17,20β‐dihydroxy‐4‐pregnen‐3‐one (17,20βP) were not consistently elevated in association with reproductive events.