title: Localization of amylin-like immunoreactivity in melanocyte-stimulating hormone-containing cells of the pars intermedia but not those of the pars distalis in the axolotl (Ambystoma mexicanum) pituitary.
abstract: Immunohistochemical techniques were employed to investigate the distribution of amylin-like immunoreactivity in the axolotl (Ambystoma mexicanum) pituitary. Amylin-immunoreactive cells were observed in the pars intermedia, and these cells were found to be immunoreactive for α-melanocyte-stimulating hormone (αMSH) as well. In contrast, αMSH-immunoreactive cells in the pars distalis were immuno-negaitive for amylin. These light microscopic findings were confirmed by immunoelectron microscopy. Amylin-immunoreactive signals were located on the haloes of presumable secretory granules in association with αMSH-immunoreactive signals in the amylin-positive cells. However, in the pars distalis, the αMSH-positive cells did not contain amylin-immunoreactive secretory granules. Western blot analysis of axolotl pituitary extracts revealed the labeling of a protein band at approximately 10.5-kDa by the anti-rat amylin serum, which was not labeled by the anti-αMSH antibody. These findings indicate that amylin secreted from MSH-producing cells in the pars intermedia may modulate MSH secretion in an autocrine fashion and may participate in MSH functions such as fatty homeostasis together with MSH.
authors.affiliation: Department of Biology, Fukuoka University of Education, Akamabunkyo-machi 1-1, Munakata, Fukuoka 811-4192, Japan. Electronic address: spiderhs@fukuoka-edu.ac.jp.
authors.forename: Hirohumi
authors.initials: H
authors.lastname: Suzuki
authors.affiliation: Brain Functions and Neuroscience Unit, Department of Oral Science, Graduate School of Dentistry, Kanagawa Dental University, Inaoka-cho 82, Yokosuka, Kanagawa 238-8580, Japan.
authors.forename: Toshiharu
authors.initials: T
authors.lastname: Yamamoto
mesh_terms: D000558:Ambystoma mexicanum / Q000033:anatomy & histology*; D029845:Amphibian Proteins / Q000378:metabolism; D000818:Animals; D048430:Cell Shape; D007150:Immunohistochemistry; D009074:Melanocyte-Stimulating Hormones / Q000378:metabolism; D010903:Pituitary Gland, Anterior / Q000166:cytology*; D052716:Pituitary Gland, Intermediate / Q000166:cytology*
chemical_list: D029845:Amphibian Proteins; D009074:Melanocyte-Stimulating Hormones
keywords: Amphibian; Amylin; Axolotl; IAPP; MSH; Pituitary