Epidermal growth factor (EGF) produces inositol phosphates and increases cytoplasmic free calcium in cultured porcine thyroid cells.
The initial signal for thyroid cell proliferation is unknown. This is the first report to show that epidermal growth factor (EGF) produces inositol phosphates and increases cytoplasmic free calcium ([Ca2+]i) in the thyroid gland. In cultured porcine thyroid cells, 10 nM EGF produces a breakdown of phosphatidylinositol and stimulates inositol phosphate production. Ten nM EGF increases [Ca2+]i, measured using fura-2, a fluorescent Ca2+ indicator; the EGF-induced [Ca2+]i response occurs immediately, reaches a maximum within several seconds, and then slowly declines. EGF stimulates production of inositol phosphates, which seem to increase [Ca2+]i. Inositol phosphate production and an increase in [Ca2+]i after EGF-stimulation may function as an initial signal for thyroid cell proliferation.
Takasu
N
N
Department of Gerontology, Endocrinology and Metabolism, School of Medicine, Shinshu University, Nagano-ken, Japan.
Takasu
M
M
Yamada
T
T
Shimizu
Y
Y
D000818:Animals; D002118:Calcium / Q000378:metabolism*; D002455:Cell Division / Q000187:drug effects; D002478:Cells, Cultured; D003593:Cytoplasm / Q000378:metabolism; D004815:Epidermal Growth Factor / Q000494:pharmacology*; D007295:Inositol Phosphates / Q000378:metabolism*; D013403:Sugar Phosphates / Q000378:metabolism*; D013552:Swine; D013961:Thyroid Gland / Q000166:cytology / Q000187:drug effects / Q000378:metabolism* / Q000648:ultrastructure
D007295:Inositol Phosphates; D013403:Sugar Phosphates; D004815:Epidermal Growth Factor; D002118:Calcium