Effect of inositol 1,4,5‐trisphosphate and GTP on calcium release from pituitary microsomes

FEBS Letters

Spät, A.¹  Kiesel, L.²  Eberhardt, Inge²  Lukács, G.L.¹  Runnebaum, B.² 

[1] Department of Physiology, Semmelweis University Medical School, PO Box 259, H-1444 Budapest, Hungary;Department of Gynecology and Obstetrics, University of Heidelberg, D-6900 Heidelberg, FRG

关键词: GTP;    Inositol trisphosphate;    Ca2+ release;    Microsome;    Polyethylene glycol;    Protein phosphorylation;    EC50;    concentration required for half-maximal effect;    IP3;    inositol 1;    4;    5-trisphosphate;    PEG;    polyethylene glycol;   

DOI  :  10.1016/0014-5793(87)81248-6

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

Microsomal vesicles from bovine anterior pituitary accumulate Ca²⁺ and maintain a steady-state ambient Ca²⁺ level of 200 nM. IP₃ and GTP both induce calcium release from the microsomal vesicles. The effect of IP₃ is inhibited by polyethylene glycol (PEG), and the effect of GTP is absolutely dependent on PEG. Half-maximal effect of IP₃ (without PEG) is 0.26 μm, the maximal calcium release attaining 7% of the A23187-releasable pool. The same values for GTP (in the presence of PEG) are 80 μM and 10%, respectively. GTP potentiates the effect of IP₃. This potentiation is not mediated by protein phosphorylation.

【 授权许可】

Unknown