Guanine nucleotides are potent secretagogues in permeabilized parathyroid cells

FEBS Letters

LeBoff, Meryl¹  Oetting, Marguerite²  Preston, Joseph¹  Swiston, Linda¹  Brown, Edward¹ 

[1] Endocrine-Hypertension Unit and Department of Medicine, Brigham and Women's Hospital, Boston, MA 02115, USA;Duke University Medical School, Durham, NC 27710, USA

关键词: PTH release Permeabilized cell Guanine nucleotide Ca2+;   

DOI  :  10.1016/0014-5793(86)81540-X

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

We studied the effects of GTP and its' analogues on PTH release in permeabilized parathyroid cells to assess their role in mediating the unusual inverse relationship between Ca²⁺ and PTH release in intact parathyroid cells. Both 10-5 M GppNHp and GTPγS, nonhydrolysable analogues of GTP, produce up to an 8-fold enhancement of PTH release, which is dose-dependent. This effect is specific for GTP analogues as we could not mimic it with other nucleotides. 10⁻³ M GDPβS, a nonhydrolysable GDP analogue, completely abolishes GppNHp-stimulated hormone release, providing further support for mediation of this effect by a guanine-nucleotide regulatory protein. In GppNHp-stimulated cells, PTH release is maximal at free [Ca²⁺] less than 200 nM and progressively decreases as the free [Ca²⁺] increases from 300 nM to 100 μM. These results suggest the presence of a guanine-nucleotide binding protein in the parathyroid cell that may play an important role in the regulation of PTH secretion by Ca²⁺ and perhaps other secretagogues.

【 授权许可】

Unknown