title: Immunohistochemical detection of corticotropin-releasing hormone (CRH) in the brain and pituitary of the hagfish, Eptatretus burgeri.
abstract: The distribution of corticotropin-releasing hormone (CRH) in the brain and pituitary of the hagfish Eptatretus burgeri, representing the earliest branch of vertebrates, was examined by immunohistochemistry to better understand the neuroendocrine system of hagfish. CRH-immunoreactive (ir) cell bodies were detected in the preoptic nucleus, periventricular preoptic nucleus, infundibular nucleus of the hypothalamus, and in the nucleus "A" of Kusunoki et al. (1982) in the medulla oblongata. In the brain, CRH-ir fibers were detected in almost all areas except for the olfactory bulb and telencephalon. Bundles of CRH-ir fibers were detected in the dorsal wall of the neurohypophysis. However, CRH-ir fibers were distant from adrenocorticotropic hormone (ACTH) cells in the adenohypophysis, as studied by dual-label immunohistochemistry. Cortisol and corticosterone were detected in the plasma by a combination of reverse-phase high performance liquid chromatography and a time-resolved fluoroimmunoassay. These results suggest that in the hagfish, CRH, ACTH, and corticosteroids exist and that CRH released in the neurohypophysis likely reaches the adenohypophysis via diffusion.
authors.affiliation: School of Marine Biosciences, Kitasato University, Sagamihara, Kanagawa 252-0373, Japan. Electronic address: amanoma@kitasato-u.ac.jp.
authors.forename: Masafumi
authors.initials: M
authors.lastname: Amano
authors.affiliation: School of Marine Biosciences, Kitasato University, Sagamihara, Kanagawa 252-0373, Japan.
authors.forename: Noriko
authors.initials: N
authors.lastname: Amiya
authors.affiliation: School of Marine Biosciences, Kitasato University, Sagamihara, Kanagawa 252-0373, Japan.
authors.forename: Takehiko
authors.initials: T
authors.lastname: Yokoyama
authors.affiliation: School of Marine Biosciences, Kitasato University, Sagamihara, Kanagawa 252-0373, Japan.
authors.forename: Kengo
authors.initials: K
authors.lastname: Onikubo
authors.affiliation: Laboratory of Fish Biology, Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya, Aichi 464-8601, Japan.
authors.forename: Naoyuki
authors.initials: N
authors.lastname: Yamamoto
authors.affiliation: School of Marine Biosciences, Kitasato University, Sagamihara, Kanagawa 252-0373, Japan.
authors.forename: Akiyoshi
authors.initials: A
authors.lastname: Takahashi
mesh_terms: D000818:Animals; D001921:Brain / Q000378:metabolism*; D003346:Corticotropin-Releasing Hormone / Q000378:metabolism*; D006196:Hagfishes / Q000378:metabolism*; D007150:Immunohistochemistry; D010902:Pituitary Gland / Q000378:metabolism*
chemical_list: D003346:Corticotropin-Releasing Hormone
keywords: ACTH; CRH; Corticosteroid; Hagfish; Immunohistochemistry