cAMP-associated inhibition of Na+-H+ exchanger in rabbit kidney brush-border membranes.

Published

Journal Article

Adenosine 3',5'-cyclic monophosphate (cAMP) inhibits the rate of bicarbonate reabsorption and the rate of Na+-H+ exchange transport in the apical membrane of the proximal convoluted tubule. To study the relation between cAMP, cAMP-dependent protein kinase, and Na+-H+ exchange transport, brush-border membrane vesicles from the rabbit kidney were phosphorylated in vitro. The rate of proton gradient-stimulated amiloride-inhibitable 22Na+ uptake was measured as an index of Na+-H+ exchange transport activity. The inclusion of cAMP (10(-6) M) in a phosphorylating solution containing ATP decreased the 10-s uptake of amiloride-sensitive sodium from 2.25 +/- 0.21 nmol/mg protein in controls to 1.94 +/- 0.19 (P less than 0.001). Incubation of vesicles in the presence of purified catalytic subunit of cAMP-dependent protein kinase inhibited the amiloride-sensitive uptake of 22Na+ at 10 s from 2.35 +/- 0.49 nmol/mg protein to 2.05 +/- 0.44 (P less than 0.005). The inhibitory effect of both cAMP and catalytic subunit of cAMP-dependent protein kinase was blocked by the specific thermostable protein inhibitor of the kinase. These studies demonstrate that activation of endogenous membrane-bound cAMP-dependent protein kinase or exposure to exogenous catalytic subunit of cAMP-dependent protein kinase inhibits the rate of Na+-H+ exchange transport in the brush-border membrane of the rabbit kidney.

Full Text

Duke Authors

Cited Authors

  • Weinman, EJ; Shenolikar, S; Kahn, AM

Published Date

  • January 1987

Published In

Volume / Issue

  • 252 / 1 Pt 2

Start / End Page

  • F19 - F25

PubMed ID

  • 3028154

Pubmed Central ID

  • 3028154

Electronic International Standard Serial Number (EISSN)

  • 2163-5773

International Standard Serial Number (ISSN)

  • 0002-9513

Digital Object Identifier (DOI)

  • 10.1152/ajprenal.1987.252.1.f19

Language

  • eng