Specific and nonspecific effects of nucleotides on hormone‐induced phosphoinositide turnover in permeabilized human pituitary tumour cells (Flow 9000)

FEBS Letters

Lo, William W.Y.¹  Hughes, John¹ 

[1] Parke-Davis Research Unit, Addenbrookes Hospital Site, Hills Road, Cambridge CB2 2QB, England

关键词: G-protein;    Nucleotide;    Phosphoinositide;    Ca2+;    Cholecystokinin;    (Flow 9000 cell);    CCK-8;    cholecystokinin octapeptide (sulphated);    ATP[S];    adenosine-5′-O-(3-thiotriphosphate);    AppNHp;    adenylylimidodiphosphate;    GTP[S];    guanosine-5′-O-(3-thiotriphosphate);    GppNHp;    guanylylimidodiphosphate;    GDP-β-S;    guanosine-5′-O-(2-thiodiphosphate);   

DOI  :  10.1016/0014-5793(87)80552-5

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

Previous studies have shown that agonist-induced inositol phosphate formation in the human embryonic pituitary cell line Flow 9000 is regulated by guanine nucleotides, and it is likely that a guanine nucleotide-binding protein is involved in coupling receptors to phosphoinositidase C (PIC) [(1986) Biochem.Soc. Trans. 14, 1135–1136]. We have now tested the specificity of various nucleotides in regulating PIC activity in the absence or presence of the hormone cholecystokinin (CCK-8) in saponin-permeabilized [³H]inositol-labelled Flow 9000 cells. We found that all nucleotides tested (i.e. CTP, UTP, ITP, TTP, GTP, GppNHp, GTP[S], ATP, AppNHp and ATP[S]) stimulated total [³H]inositol phosphate (³H]IP) formation in a dose-dependent manner with similar potency and efficacy. However, only guanine nucleotides significantly enhanced CCK-8 stimulation of [³H]IP production. These results indicate a physiological role for guanine nucleotides in regulating hormone-induced phosphoinositide turnover. In addition, the effects of nucleotides on calcium-dependent PIC activity are discussed.

【 授权许可】

Unknown