Protein kinase A, cytosolic calcium, and phosphate uptake in human proximal renal cells.

Journal Article (Journal Article)

Phosphate uptake by proximal renal cells derived from the human kidney occurs by a saturable process that is approximately 85% dependent on the presence of sodium. Kinetic analysis is consistent with two distinct transport events with Km of 0.08 and 0.63 mM and Vmax of 3.4 and 11.0 min-1, respectively. Parathyroid hormone (PTH), isoproterenol, and prostaglandin E2 (PGE2) increased cellular adenosine 3',5'-cyclic monophosphate (cAMP). PTH-stimulated cAMP prevented binding of the photolabel 8-azido[32P]cAMP with a half-maximal effective concentration (EC50) of 1 nM PTH, 30-fold lower than the EC50 for intracellular cAMP accumulation. These data are qualitatively similar to those observed in OK cells. PTH did not inhibit phosphate uptake in human cells, although it activated cAMP-dependent protein kinase and increased cytosolic calcium. Thus phosphate uptake in human proximal renal cells maintained in short-term culture is unresponsive to PTH in spite of increased cytosolic calcium and activation of the cAMP pathway.

Full Text

Duke Authors

Cited Authors

  • Middleton, JP; Dunham, CB; Onorato, JJ; Sens, DA; Dennis, VW

Published Date

  • October 1989

Published In

Volume / Issue

  • 257 / 4 Pt 2

Start / End Page

  • F631 - F638

PubMed ID

  • 2478035

International Standard Serial Number (ISSN)

  • 0002-9513

Digital Object Identifier (DOI)

  • 10.1152/ajprenal.1989.257.4.F631


  • eng

Conference Location

  • United States