Partial characterization of four forms of immunoreactive gonadotropin-releasing hormone in the brain and terminal nerve of the spiny dogfish (Elasmobranchii; Squalus acanthias)

Abstract

Four forms of immunoreactive GnRH have been detected in tissue extracts of both whole brains and terminal nerves from the spiny dogfish ( Squalus acanthias). The GnRH forms were characterized using reverse-phase high pressure liquid chromatography (HPLC) and immunological recognition with four different antisera. Three of these forms possess immunological and chromatographic properties consistent with known forms of GnRH: mammalian GnRH, chicken GnRH-II and salmon GnRH. An additional form, with an HPLC elution position intermediate between chicken GnRH-II and salmon GnRH appears to be a new structure of GnRH. The presence of all four GnRH forms in the terminal nerve suggests a lack of regional specificity of the expressed forms of GnRH in the brain.