title: Plasma-sulfated C21-steroids increase during the periovulatory period in female common wolffish and are influenced by temperature during vitellogenesis.
abstract: Plasma concentrations of steroids during the periovulatory period were measured in female common wolffish reared at three different temperatures. Steroids were quantified by radioimmunoassay (RIA). Two "broad-spectrum specificity" RIAs-one which detects C21-steroids with a 17,20beta-dihydroxyl configuration (17,20beta-steroids) and the other which detects C21-steroids with a 5beta-reduced, 3alpha-hydroxyl configuration (5beta,3alpha-steroids)-picked up very large amounts of cross-reacting material (1.7 microg ml(-1) in one fish) in the sulfate fraction of plasma from ovulating females. Reverse-phase high-performance liquid chromatography and thin-layer chromatography revealed two major steroids: 5beta-pregnane-3alpha,17,20beta-triol (80%) and 5beta-pregnane-3beta,17,20beta-triol (20%). The sulfated forms of these steroids were elevated 4 to 6 days before and during ovulation, compared with those of females in vitellogenic and postspawning condition, in which concentrations were below 2.0 ng ml(-1). In the three groups of fish held at 4, 8, and 12 degrees C during vitellogenesis, but returned to 4 degrees C just prior to the spawning season, the mean concentrations of sulfated 17,20beta-steroids in ovulating females were 530, 635, and 325 ng ml(-1), respectively. The corresponding concentrations of free 17,20beta-dihydroxy-4-pregnen-3-one (17,20beta-P; the maturation-inducing steroid in many teleosts) were 0.88, 0.86, and 0.57 ng ml(-1), respectively. Only minute amounts of 17,20beta,21-P and its sulfated derivatives were detected. Significantly lower steroid concentrations in the 12 degrees C group indicate that steroid synthesis and/or metabolism during the periovulatory period are influenced by the temperature experienced during vitellogenesis. In male fish, plasma concentrations of both sulfated 17,20beta-steroids and free 17,20beta-P were low (< 2.0 ng ml(-1)) at all times.
authors.affiliation: Norwegian College of Fishery Science, University of Tromsø, Norway.
authors.forename: H
authors.initials: H
authors.lastname: Tveiten
authors.forename: A P
authors.initials: AP
authors.lastname: Scott
authors.forename: H K
authors.initials: HK
authors.lastname: Johnsen
mesh_terms: D000818:Animals; D005260:Female; D005399:Fishes / Q000097:blood*; D006908:Hydroxyprogesterones / Q000097:blood; D010060:Ovulation; D011279:Pregnanetriol / Q000097:blood; D011863:Radioimmunoassay; D012621:Seasons; D012680:Sensitivity and Specificity; D013256:Steroids / Q000097:blood*; D013431:Sulfates / Q000097:blood*; D013696:Temperature; D014818:Vitellogenesis
chemical_list: D006908:Hydroxyprogesterones; D013256:Steroids; D013431:Sulfates; C007433:17,20-dihydroxy-4-pregnen-3-one; D011279:Pregnanetriol