Rat testis immunoreactive LH-RH differs structurally from hypothalamic LH-RH

Luteinizing hormone releasing hormone immunoreactivity (LH-RH-IR) has been identified in acetic acid extracts of adult rat testes and partially purified by immunoaffinity chromatography. On Sephadex G-100 this material separated into four major peaks of >100K, ～32K, ～5K and ≤4K daltons. The ≤4K peak of LH-RH-IR eluted later than synthetic hypothalamic LH-RH decapeptide on Sephadex G-25. Antibody binding studies on the various LH-RH-IR species with antisera specific for different regions of synthetic LH-RH decapeptide indicate that all the testicular LH-RH-IR molecules have C-terminal immunological homology with the hypothalmic decapeptide but differ towards the N-terminus of the decapeptide sequence.