Possible involvement of ryanodine receptor-mediated intracellular calcium release in the effect of corticotropin-releasing factor on adrenocorticotropin secretion.
We examined the role of intracellular calcium release in the regulation of CRH-induced ACTH secretion using the AtT20 corticotroph cell line. We found that ruthenium red, an inhibitor of ryanodine receptor, substantially diminished the secretory response, whereas Xestospongin C, an inositol 1,4,5-triphosphate receptor antagonist, had no effect. Expression of two ryanodine receptor subtypes (RyR1 and RyR3) was confirmed by RT-PCR. We also found that caffeine, a ryanodine receptor agonist, significantly stimulated, whereas thapsigargin, which causes depletion of intracellular calcium store, markedly diminished, the ACTH release. These results suggest that ryanodine receptor-mediated calcium-induced calcium release is involved in the regulation of CRH-induced ACTH release.
Department of Medicine, Nagoya University Graduate School of Medicine and Hospital, Japan.
Etsuko
E
Yamamori
Yasumasa
Y
Iwasaki
Yutaka
Y
Oki
Masanori
M
Yoshida
Masato
M
Asai
Machiko
M
Kambayashii
Yutaka
Y
Oiso
Nobuo
N
Nakashima
D000324:Adrenocorticotropic Hormone / Q000378:metabolism*; D000818:Animals; D002110:Caffeine / Q000494:pharmacology; D002118:Calcium / Q000378:metabolism*; D015220:Calcium Channels / Q000378:metabolism; D002460:Cell Line; D003346:Corticotropin-Releasing Hormone / Q000378:metabolism*; D004791:Enzyme Inhibitors / Q000494:pharmacology; D053496:Inositol 1,4,5-Trisphosphate Receptors; D051379:Mice; D010726:Phosphodiesterase Inhibitors / Q000494:pharmacology; D010902:Pituitary Gland / Q000166:cytology*; D012333:RNA, Messenger / Q000032:analysis; D018160:Receptors, Cytoplasmic and Nuclear / Q000378:metabolism; D019837:Ryanodine Receptor Calcium Release Channel / Q000235:genetics / Q000378:metabolism*; D015398:Signal Transduction / Q000187:drug effects / Q000502:physiology; D019284:Thapsigargin / Q000494:pharmacology
D015220:Calcium Channels; D004791:Enzyme Inhibitors; D053496:Inositol 1,4,5-Trisphosphate Receptors; D010726:Phosphodiesterase Inhibitors; D012333:RNA, Messenger; D018160:Receptors, Cytoplasmic and Nuclear; D019837:Ryanodine Receptor Calcium Release Channel; D002110:Caffeine; D019284:Thapsigargin; D000324:Adrenocorticotropic Hormone; D003346:Corticotropin-Releasing Hormone; D002118:Calcium