These tools will no longer be maintained as of December 31, 2024. Archived website can be found here. PubMed4Hh GitHub repository can be found here. Contact NLM Customer Service if you have questions.


Pubmed for Handhelds

PUBMED FOR HANDHELDS

Search MEDLINE/PubMed

  • Title: Role of protein kinase C in the adaptive increase in Na-H antiporter in respiratory acidosis.
    Author: Pahlavan P, Wang LJ, Sack E, Arruda JA.
    Journal: J Am Soc Nephrol; 1993 Oct; 4(4):1079-86. PubMed ID: 8286716.
    Abstract:
    Chronic respiratory acidosis stimulates the Vmax of the renal brush border Na-H antiporter. The activation of protein kinase C (PKC) by phorbol esters stimulates the activity of the renal Na-H antiporter. In this study, the hypothesis that PKC plays a role in the adaptive increase of the renal brush border Na-H antiporter activity to respiratory acidosis was tested. In vivo respiratory acidosis was associated with an increase in in vitro Na-H antiporter activity and also with an increase in brush border membrane PKC activity, without changes in PKC activity in cytosol or basolateral membranes. Na-H antiporter activity, assessed as the amiloride-sensitive component of 22Na uptake, was measured in cultured proximal tubule cells exposed to 10% CO2 for 48 h. Na-H antiporter activity was significantly higher in cells exposed to 10% CO2 than in those exposed to 5% CO2. To evaluate the role of PKC, cultured cells were depleted of PKC by exposure to the active phorbol ester phorbol 12-myristate 13-acetate (PMA; 10(-7) or 10(-6) M) for 48 h before exposure to 10% CO2. In the presence of 10% CO2, Na-H antiporter activity was significantly lower in PKC-depleted cells than in control. In addition, sphingosine, an inhibitor of PKC, also prevented the adaptation of the Na-H antiporter to 10% CO2 as compared with 5% CO2. In cells treated with the inactive analog 4 alpha-PMA, 22Na uptake was not different than that in control. PMA-treated cells also had a decrease in Na-H antiporter activity during exposure to 5% CO2.(ABSTRACT TRUNCATED AT 250 WORDS)
    [Abstract] [Full Text] [Related] [New Search]