Cloning of corticotropin-releasing hormone (CRH) precursor cDNA and immunohistochemical detection of CRH peptide in the brain of the Japanese eel, paying special attention to gonadotropin-releasing hormone.
The stress-related corticotropin-releasing hormone (CRH) was first identified by isolation of its cDNA from the brain of the Japanese eel Anguilla japonica. CRH cDNA encodes a signal peptide, a cryptic peptide and CRH (41 amino acids). The sequence homology to mammalian CRH is high. Next, the distribution of CRH-immunoreactive (ir) cell bodies and fibers in the brain and pituitary were examined by immunohistochemistry. CRH-ir cell bodies were detected in several brain regions, e.g., nucleus preopticus pars magnocellularis, nucleus preopticus pars gigantocellularis and formatio reticularis superius. In the brain, CRH-ir fibers were distributed not only in the hypothalamus but also in various regions. Some CRH-ir fibers projected to adrenocorticotropic hormone (ACTH) cells in the rostral pars distalis of the pituitary and also the α-melanocyte-stimulating hormone (α-MSH) cells in the pars intermedia of the pituitary. Finally, the neuroanatomical relationship between the CRH neurons and gonadotropin-releasing hormone (GnRH) neurons was examined by dual-label immunohistochemistry. CRH-ir fibers were found to be in close contact with GnRH-ir cell bodies in the hypothalamus and in the midbrain tegmentum and GnRH-ir fibers were in close contact with CRH-ir cell bodies in the nucleus preopticus pars magnocellularis. These results suggest that CRH has some physiological functions other than the stimulation of ACTH and α-MSH secretion and that reciprocal connections may exist between the CRH neurons and GnRH neurons in the brain of the Japanese eel.
School of Marine Biosciences, Kitasato University, Sagamihara, Kanagawa, 252-0373, Japan, amanoma@kitasato-u.ac.jp.
Masafumi
M
Amano
Nanami
N
Mizusawa
Kataaki
K
Okubo
Noriko
N
Amiya
Kanta
K
Mizusawa
Hiroaki
H
Chiba
Naoyuki
N
Yamamoto
Akiyoshi
A
Takahashi
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D001921:Brain / Q000378:metabolism*; D003001:Cloning, Molecular; D003346:Corticotropin-Releasing Hormone / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D018076:DNA, Complementary / Q000235:genetics*; D004524:Eels / Q000235:genetics*; D005260:Female; D007987:Gonadotropin-Releasing Hormone / Q000378:metabolism*; D007150:Immunohistochemistry; D007564:Japan; D008297:Male; D008969:Molecular Sequence Data; D010902:Pituitary Gland / Q000166:cytology / Q000378:metabolism; D017386:Sequence Homology, Amino Acid
D018076:DNA, Complementary; D007987:Gonadotropin-Releasing Hormone; D003346:Corticotropin-Releasing Hormone