Identification of His5, Trp7, Tyr8-GnRH (chicken GnRH II) in amphibian brain

doi:10.1016/0196-9781(86)90102-6

Peptides

Volume 7, Issue 5, September–October 1986, Pages 827-834

https://doi.org/10.1016/0196-9781(86)90102-6 Get rights and content

Abstract

GnRH immunoreactive and bioactive peptides in Xenopus laevis brain extract were investigated by high performance liquid chromatography (HPLC), radioimmunoassay with region-specific antisera raised against GnRH (mammalian), His⁵, Trp⁷, Tyr⁸-GnRH (chicken II) and Tyr³,Leu⁵,Glu⁶,Trp⁷,Lys⁸-GnRH (lamprey), and by assessment of biological activity. Two immunoreactive peptides eluted in the same positions as GnRH and His⁵,Trp⁷,Tyr⁸-GnRH respectively in HPLC systems which were specifically designed to separate four known natural vertebrate GnRHs (mammalian, chicken I and II, salmon). The immunological properties of these two immunoreactive peaks, determined by relative interaction with three region-specific antisera raised against mammalian GnRH and two specific His⁵,Trp⁷,Tyr⁸-GnRH antisera, were identical to those of GnRH and His⁵,Trp⁷,Tyr⁸-GnRH. The immunoreactive peak co-eluting with His⁵,Trp⁷,Tyr⁸-GnRH represented approximately one-third of the total brain GnRH. Both immunoreactive peaks stimulated luteinizing hormone (LH) release in a chicken dispersed pituitary cell bioassay, and the amounts of LH release stimulated by the two peaks were appropriate for these peaks being GnRH and His⁵,Trp⁷,Tyr⁸-GnRH. A small hydrophobic peak with GnRH immunoreactivity eluted in the same position as Trp⁷,Leu⁸-GnRH (salmon), while Gln⁸-GnRH (chicken I) and lamprey GnRH were not detected. Two additional rather hydrophilic peptides cross-reacted with a COOH-terminus-directed antiserum and had LH-releasing activity. LH-releasing activity was also detected in hydrophobic HPLC fractions. In summary, these data provide evidence for the presence of both GnRH and a second peptide with properties identical to His⁵,Trp⁷,Tyr⁸-GnRH in X. laevis brain. The finding in amphibian brain of His⁵,Trp⁷,Tyr⁸-GnRH, which has previously been described in species from bird, reptile and fish classes, lends support to our hypothesis that this widespread structural variant may represent an early-evolved and conserved form of GnRH.

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Identification of His5, Trp7, Tyr8-GnRH (chicken GnRH II) in amphibian brain

Abstract

Biochem Biophys Res Commun

Neuropeptides

Peptides

Trends Neurosci

Gen Comp Endocrinol

Gen Comp Endocrinol

J Biol Chem

J Biol Chem

Peptides

Peptides

Gen Comp Endocrinol

Gen Comp Endocrinol

Gen Comp Endocrinol

Life Sci

Gen Comp Endocrinol

Gen Comp Endocrinol

Neuropeptides

J Biol Chem

Gen Comp Endocrinol

The preparation and specificity of antibody to thyrotropin releasing hormone

Endocrinology

Non-mammalian luteinizing hormone-releasing factor (LRF) in tadpole and frog brain

Soc Neurosci Abstr

Dosage radio-immunologique homologue d'un facteur hypothalamique de stimulation de la fonction gonadotrope hypophysaire de Saumon s-Gn-RH

C R Acad Seances [III]

Luteinizing hormone-releasing hormone: sequential versus conformational specificity of antiluteinizing hormone-releasing hormone sera

Endocrinology

A radioimmunoassay for avian luteinizing hormone

J Endocrinol

Identification of His⁵, Trp⁷, Tyr⁸-GnRH (chicken GnRH II) in amphibian brain