title: Fundulus heteroclitus gonadotropins.5: Small scale chromatographic fractionation of pituitary extracts into components with different steroidogenic activities using homologous bioassays.
abstract: Fractionation and characterization of gonadotropins (GtH) from Fundulus heteroclitus pituitary extracts were carried out using a biocompatible liquid chromatographic procedure (Pharmacia FPLC system). Chromatographic fractions were monitored for gonadotropic activities (induction of oocyte maturation and steroid production) using homologous follicle bioassays in vitro. Size-exclusion chromatography eluted gonadotropic activity in one major protein peak (Mr approximately 30,000). Anion-exchange and hydrophobic-interaction chromatography (HIC) yielded two distinct peaks of 17beta-estradiol (E2)- and 17alpha-hydroxy,20beta-dihydroprogesterone (DHP)-promoting activity with associated oocyte maturation. Two-dimensional chromatography (chromatofocusing followed by HIC) resolved pituitary extracts into two active fractions; both induced E2 synthesis, but one was relatively poor in eliciting DHP and testosterone production. Thus, using homologous bioassays, at least two quantitatively different gonadotropic (steroidogenic) activities: an E2-promoting gonadotropin (GtH I-like) and a DHP-promoting gonadotropin (GtH II-like), which has a lower isoelectric point but greater hydrophobicity than the former, can be distinguished from F. heteroclitus pituitaries by a variety of chromatographic procedures. This study complements previous biochemical and molecular data in F. heteroclitus and substantiates the duality of GtH function in a multiple-spawning teleost.
authors.affiliation: Barry University, School of Natural & Health Sciences, Miami Shores, Florida 33161, USA. plin@mail.barry.edu
authors.forename: Yu-Wai Peter
authors.initials: YW
authors.lastname: Lin
authors.forename: Teresa R
authors.initials: TR
authors.lastname: Petrino
authors.forename: Robin A
authors.initials: RA
authors.lastname: Wallace
mesh_terms: D004092:20-alpha-Dihydroprogesterone / Q000096:biosynthesis; D000818:Animals; D001681:Biological Assay / Q000379:methods; D002845:Chromatography / Q000379:methods*; D004958:Estradiol / Q000096:biosynthesis; D005260:Female; D023781:Fundulidae; D006065:Gonadotropins, Pituitary / Q000032:analysis* / Q000494:pharmacology; D008297:Male; D006080:Ovarian Follicle / Q000187:drug effects / Q000378:metabolism; D010902:Pituitary Gland / Q000737:chemistry; D013739:Testosterone / Q000096:biosynthesis
chemical_list: D006065:Gonadotropins, Pituitary; D004092:20-alpha-Dihydroprogesterone; C001421:20 beta-dihydroprogesterone; D013739:Testosterone; D004958:Estradiol