Fig. 6.

Effect of metabolic acidosis on Rhcg expression in intercalated cells and principal cells. Top: metabolic acidosis increases ∼4-fold the amount of Rhcg present in the apical plasma membrane in both intercalated cells and principal cells in the inner stripe of the outer medulla. Increased apical plasma membrane expression can result from either an increased proportion of total Rhcg present in the apical membrane, i.e., changes in subcellular distribution, or from increased total cellular Rhcg. Middle: proportion of total cellular Rhcg present in the apical plasma membrane in both intercalated and principal cells in response to metabolic acidosis. In both cell types, there is a significant increase in the proportion of total cellular Rhcg present in the apical plasma membrane, but the relative increase is substantially greater in the intercalated cell. Bottom: effect of metabolic acidosis on total cellular Rhcg expression. In both intercalated cells and principal cells, there is a significant increase in total cellular Rhcg, but the relative increase is substantially greater in the principal cell. In top and bottom panels, separate scales are used on the right, for the principal cell, because of differences in absolute level of Rhcg expression. Data are from Ref. 85.