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Presence of luteinizing hormone‐releasing hormone fragments in the rhesus monkey forebrain
Author(s) -
Terasawa Ei,
Busser Brian W.,
Luchansky Laure L.,
Sherwood Nancy M.,
Jennes Lothar,
Millar Robert P.,
Glucksman Mark J.,
Roberts James L.
Publication year - 2001
Publication title -
journal of comparative neurology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.855
H-Index - 209
eISSN - 1096-9861
pISSN - 0021-9967
DOI - 10.1002/cne.1364
Subject(s) - biology , forebrain , medicine , endocrinology , in situ hybridization , hormone , luteinizing hormone , antiserum , gonadotropin releasing hormone , microbiology and biotechnology , messenger rna , central nervous system , antibody , biochemistry , gene , genetics
Previously, we have shown that two types of luteinizing hormone‐releasing hormone (LHRH) ‐like neurons, “early” and “late” cells, were discernible in the forebrain of rhesus monkey fetuses by using antiserum GF‐6, which cross‐reacts with several forms of LHRH. The “late” cells that arose from the olfactory placode of monkey fetuses at embryonic days (E) 32–E36, are bona fide LHRH neurons. The “early” cells were found in the forebrain at E32–E34 and settled in the extrahypothalamic area. The molecular form of LHRH in “early” cells differs from “late” cells, because “early” cells were not immunopositive with any specific antisera against known forms of LHRH. In this study, we investigated the molecular form of LHRH in the “early” cells in the nasal regions and brains of 13 monkey fetuses at E35 to E78. In situ hybridization studies suggested that both “early” and “late” LHRH cells expressed mammalian LHRH mRNA. Furthermore, “early” cells predominantly contain LHRH 1‐5 ‐like peptide and its cleavage enzyme, metalloendopeptidase E.C.3.4.24.15 (EP24.15), which cleaves LHRH at the Tyr 5 ‐Gly 6 position. This conclusion was based on immunocytochemical labeling with various antisera, including those against LHRH 1‐5 , LHRH 4‐10 , or EP24.15, and on preabsorption tests. Therefore, in primates, a group of neurons containing mammalian LHRH mRNA arises at an early embryonic stage before the migration of bona fide LHRH neurons, and is ultimately distributed in the extrahypothalamic region. These extrahypothalamic neurons contain LHRH fragments, rather than fully mature mammalian LHRH. The origin and function of these neurons remain to be determined. J. Comp. Neurol. 439:491‐504, 2001. © 2001 Wiley‐Liss, Inc.