title: Mechanisms of TRH-induced GH release (paradoxical response) in human somatotroph adenoma cells.
abstract: The mechanisms of paradoxical TRH response in human somatotroph adenoma cells were investigated using intracellular calcium measurement and static incubation assay. Intracellular calcium measurement revealed that TRH induces a biphasic response: a transient increase followed by a sustained plateau. The transient phase was due to the calcium release from IP(3)-regulated intracellular calcium store and the subsequent sustained phase was due to the calcium influx through the voltage-gated calcium channels. The signal transduction mechanism of the calcium plateau involved protein kinase C. These calcium responses, especially the second phase, was responsible for the TRH-induced GH release.
authors.affiliation: Department of Nephrology and Endocrinology, University of Tokyo Faculty of Medicine, Tokyo.
authors.forename: Hiroko
authors.initials: H
authors.lastname: Okinaga
authors.forename: Koji
authors.initials: K
authors.lastname: Takano
authors.forename: Shuhei
authors.initials: S
authors.lastname: Hayashi
authors.forename: Junko
authors.initials: J
authors.lastname: Yasufuku-Takano
authors.forename: Akira
authors.initials: A
authors.lastname: Teramoto
authors.forename: Toshiro
authors.initials: T
authors.lastname: Fujita
mesh_terms: D000236:Adenoma / Q000737:chemistry / Q000378:metabolism* / Q000473:pathology; D002118:Calcium / Q000378:metabolism; D015220:Calcium Channels / Q000187:drug effects / Q000502:physiology; D049912:Growth Hormone-Secreting Pituitary Adenoma / Q000737:chemistry / Q000378:metabolism* / Q000473:pathology; D019382:Human Growth Hormone / Q000378:metabolism*; D006801:Humans; D011493:Protein Kinase C / Q000378:metabolism; D011863:Radioimmunoassay; D015398:Signal Transduction; D013973:Thyrotropin-Releasing Hormone / Q000494:pharmacology*; D014407:Tumor Cells, Cultured
chemical_list: D015220:Calcium Channels; D019382:Human Growth Hormone; D013973:Thyrotropin-Releasing Hormone; D011493:Protein Kinase C; D002118:Calcium