Acid loading in vivo and low pH in culture increase angiotensin receptor expression: enhanced ammoniagenic response to angiotensin II.

The proximal tubule defends the body against acid challenges by enhancing its production and secretion of ammonia. Our previous studies demonstrated an enhanced ammoniagenic response of the proximal tubule to ANG II added to the lumen in vitro after an in vivo acid challenge. The present study examined the effect of NH(4)Cl acid loading in vivo on renal cortical type 1 ANG II (AT(1)) receptor expression, the effect of low pH on AT(1) receptor expression in a proximal tubule cells in culture, and their response to ANG II.