Distribution of endothelin 3-like immunoreactivity in gonadotrophs of the bullfrog (Rana catesbeiana) pituitary.
Immunohistochemical and immunocytochemical techniques were employed to investigate the distribution of endothelin 3 (ET3)-like immunoreactivity in the pituitary of the bullfrog, Rana catesbeiana. ET3-immunoreactive (ET3-IR) cells were scattered all over the pars distalis of the female pituitary; however, only a few ET3-IR cells were observed in the male pituitary. ET3-IR cells were found to correspond to cells immunostained with monoclonal antibodies against the beta-subunit of bullfrog LH (fLH beta) or monoclonal antibodies against the beta-subunit of bullfrog FSH (fFSH beta) at the light microscopic level. However, we could not find ET3-IR cells which were immunoreactive for other pituitary hormones. So far, all ET3-IR cells showed both fLH beta and fFSH beta immunoreactivity. About 24% of the fLH beta-IR cells and about 33% of the fFSH beta-IR cells showed ET3-like immunoreactivity. Immunoelectron microscopic analysis using colloidal gold revealed the coexistence of ET3-like substance(s) and gonadotropins within the same granules. This study demonstrated the presence of ET3-like peptide(s) in bullfrog gonadotrophs, suggesting the possible participation of ET3 in regulating pituitary function as an autocrine and/or paracrine hormone.
Suzuki
H
H
Department of Biology, Kanagawa Dental College, Yokosuka, Japan.
Yamamoto
T
T
Kikuyama
S
S
Uemura
H
H
D000818:Animals; D000911:Antibodies, Monoclonal; D019334:Endothelin-3 / Q000276:immunology / Q000378:metabolism*; D005260:Female; D007074:Immunoglobulin G / Q000276:immunology; D007150:Immunohistochemistry; D008297:Male; D016253:Microscopy, Immunoelectron; D010902:Pituitary Gland / Q000378:metabolism* / Q000648:ultrastructure; D011817:Rabbits; D011892:Rana catesbeiana / Q000378:metabolism*; D012621:Seasons
D000911:Antibodies, Monoclonal; D019334:Endothelin-3; D007074:Immunoglobulin G