Mechanism of adrenomedullin-induced prolactin release from human prolactin-releasing adenoma cells.
The mechanism of adrenomedullin-induced prolactin release was investigated in prolactin-secreting human pituitary adenoma cells by intracellular calcium measurement and static incubation study. Adrenomedullin stimulated prolactin release in a concentration-dependent manner. The stimulation was dependent on extracellular sodium and voltage-gated calcium channels. PKA inhibitor attenuated adrenomedullin-induced prolactin release. The mechanism of adrenomedullin action was studied by fura 2-based intracellular calcium measurement. Adrenomedullin increased intracellular calcium concentration in these cells. The increase was dependent on extracellular sodium and voltage-gated calcium channels. PKA inhibitor attenuated the calcium response. These data indicate that adrenomedullin stimulates prolactin release by modulating calcium influx through voltage-gated calcium channels dependently on extracellular sodium. Mechanisms involving sodium-influx mediated depolarization may play a role in the stimulatory action.
Kimata-Hayashi
Nako
N
Department of Nephrology and Endocrinology, University of Tokyo Faculty of Medicine, Tokyo.
Takano
Koji
K
Yasufuku-Takano
Junko
J
Teramoto
Akira
A
Fujita
Toshiro
T
D053607:Adrenomedullin; D002118:Calcium / Q000378:metabolism; D015220:Calcium Channels / Q000187:drug effects; D004305:Dose-Response Relationship, Drug; D016257:Fura-2; D006801:Humans; D047908:Intracellular Signaling Peptides and Proteins / Q000494:pharmacology; D010455:Peptides / Q000494:pharmacology*; D010911:Pituitary Neoplasms / Q000737:chemistry / Q000378:metabolism* / Q000473:pathology; D011388:Prolactin / Q000378:metabolism*; D015175:Prolactinoma / Q000737:chemistry / Q000378:metabolism* / Q000473:pathology; D012964:Sodium / Q000378:metabolism; D014407:Tumor Cells, Cultured
D015220:Calcium Channels; D047908:Intracellular Signaling Peptides and Proteins; D010455:Peptides; C015482:protein kinase modulator; D053607:Adrenomedullin; D011388:Prolactin; D012964:Sodium; D002118:Calcium; D016257:Fura-2