Increase in cytoplasmic Ca2+ and stimulation of calcitonin secretion from human medullary thyroid carcinoma cells by the gastrin-releasing peptide.
Examination was made of the effects of gastrin-releasing peptide (GRP) on human medullary thyroid carcinoma cells (TT cells). GRP stimulated calcitonin(CT) release in a concentration-dependent manner at 0.1-1000 nmol/l. On adding forskolin along with GRP, CT release was greater than by GRP alone. The stimulatory effect of A23187 was not additive. Intracellular free calcium concentration ([Ca2+]i) was measured for individual TT cells loaded with fura-2. The addition of GRP caused a rapid and transient rise in [Ca2+]i in a concentration-dependent manner followed by a sustained increase in [Ca2+]i. In the medium without Ca2+, this sustained increase did not occur and the concentration of CT release from TT cells by GRP was reduced by approximately a half. GRP would thus appear to be importantly involved in the regulation of thyroid C cell function through modulation of [Ca2+]i.
Abe
Y
Y
Department of Internal Medicine, School of Medicine Kitasato University, Sagamihara, Japan.
Kanamori
A
A
Yajima
Y
Y
Kameya
T
T
D000001:Calcimycin / Q000494:pharmacology; D002116:Calcitonin / Q000378:metabolism*; D002118:Calcium / Q000378:metabolism*; D002460:Cell Line; D005576:Colforsin / Q000494:pharmacology; D003593:Cytoplasm / Q000187:drug effects / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D004533:Egtazic Acid / Q000494:pharmacology; D016257:Fura-2; D019886:Gastrin-Releasing Peptide; D005768:Gastrointestinal Hormones / Q000494:pharmacology*; D006801:Humans; D007700:Kinetics; D010455:Peptides / Q000494:pharmacology*; D013964:Thyroid Neoplasms / Q000378:metabolism; D010566:Virulence Factors, Bordetella / Q000494:pharmacology
D005768:Gastrointestinal Hormones; D010455:Peptides; D010566:Virulence Factors, Bordetella; D005576:Colforsin; D000001:Calcimycin; D004533:Egtazic Acid; D019886:Gastrin-Releasing Peptide; D002116:Calcitonin; D002118:Calcium; D016257:Fura-2