[Trp7,Leu8]LH-RH in reptilian brain.

Luteinizing hormone-releasing hormone (LH-RH) immunoreactive peptides in acetic acid extracts of lizard (Cordylis nigra) brain were studied by high performance liquid chromatography (HPLC) and radioimmunoassay with region-specific antisera. Four different LH-RH immunoreactive peptides were detected. The major form co-eluted with salmon brain LH-RH, [Trp7,Leu8]LH-RH, in a cation exchange and three reverse phase HPLC systems which were specifically designed to separate a range of LH-RH analogues. The interaction of this major LH-RH immunoreactive peptide with a number of antisera directed against different regions of mammalian, chicken and salmon LH-RH was similar to the relative interaction of [Trp7,Leu8]LH-RH with these antisera. These data strongly indicate that the major form of lizard brain LH-RH is identical to salmon brain LH-RH [( Trp7,Leu8]LH-RH). The three additional molecular forms of immunoreactive LH-RH in lizard brain appear to differ from mammalian LH-RH in the middle to C-terminal region of the molecule.