Vasoactive intestinal peptide increases intracellular free calcium in rat and human pituitary tumour cells in vitro
1987; Bioscientifica; Volume: 114; Issue: 1 Linguagem: Inglês
10.1677/joe.0.1140119
ISSN1479-6805
AutoresR. A. Prysor-Jones, J. J. Silverlight, J. S. Jenkins,
Tópico(s)Coagulation, Bradykinin, Polyphosphates, and Angioedema
ResumoABSTRACT Prolactin secretion by a human pituitary tumour cell line produced in our laboratory was stimulated by TRH, vasoactive intestinal peptide (VIP) and epithelial growth factor (EGF). All raised the intracellular concentration of free calcium (Ca 2+ i ) of cells loaded with a fluorescent quinoline Ca 2+ indicator in suspension, but the effect of TRH was much more rapid and less prolonged than that of VIP and EGF. Both TRH and VIP also increased Ca 2+ i in GH 3 rat pituitary tumour cells, but in this cell line the effect of VIP was only found in attached cells grown on cover-slips. In both human and rat cell lines, the increase in Ca 2+ i produced by TRH was independent of extracellular calcium, whereas this was a requirement for the action of VIP and EGF. It is concluded that the prolactin secretogogues, VIP and probably EGF, increase Ca 2+ i through an effect on plasma membrane calcium channels and that this effect differs from that of TRH. J. Endocr. (1987) 114, 119–123
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