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


Journal Article

Phosphate uptake by proximal renal cells derived from the human kidney occurs by a saturable process that is ~ 85% dependent on the presence of sodium. Kinetic analysis is consistent with two distinct transport events with K(m) of 0.08 and 0.63 mM and V(max) of 3.4 and 11.0 nmol · mg-1 · 3 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.

Duke Authors

Cited Authors

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

Published Date

  • January 1, 1989

Published In

Volume / Issue

  • 257 / 4

International Standard Serial Number (ISSN)

  • 0002-9513

Citation Source

  • Scopus