Lin Yu-Wai Peter, Petrino Teresa R, Wallace Robin A
Barry University, School of Natural & Health Sciences, Miami Shores, Florida 33161, USA.
Reprod Biol Endocrinol. 2004 Mar 24;2:14. doi: 10.1186/1477-7827-2-14.
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.
使用生物相容性液相色谱法（Pharmacia FPLC系统）对来自底鳉垂体提取物中的促性腺激素（GtH）进行了分级分离和特性鉴定。使用体外同源卵泡生物测定法监测色谱级分的促性腺活性（卵母细胞成熟诱导和类固醇生成）。尺寸排阻色谱法在一个主要蛋白峰（Mr约为30,000）中洗脱了促性腺活性。阴离子交换色谱法和疏水相互作用色谱法（HIC）产生了两个不同的峰，分别具有促进17β-雌二醇（E2）和17α-羟基-20β-二氢孕酮（DHP）生成的活性，并伴有卵母细胞成熟。二维色谱法（聚焦色谱法后接HIC）将垂体提取物分离为两个活性级分；两者均诱导E2合成，但其中一个在引发DHP和睾酮生成方面相对较差。因此，通过同源生物测定法，至少可以区分出两种数量上不同的促性腺（类固醇生成）活性：一种促进E2生成的促性腺激素（类GtH I）和一种促进DHP生成的促性腺激素（类GtH II），后者的等电点较低但疏水性比前者强，通过多种色谱方法可从底鳉垂体中区分出来。本研究补充了底鳉先前的生化和分子数据，并证实了多产硬骨鱼中GtH功能的双重性。
