Expression and distribution of renal vacuolar proton-translocating adenosine triphosphatase in response to chronic acid and alkali loads in the rat.

Abstract

Renal hydrogen ion excretion increases with chronic acid loads and decreases with alkali loads. We examined the mechanism of adaptation by analyzing vacuolar proton-translocating adenosine triphosphatase (H' ATPase) 31-kD subunit protein and mRNA levels, and immunocytochemical distribution in kidneys from rats subjected to acid or alkali loads for 1,3,5,7, and 14 d. Acid-and alkali-loaded rats exhibited adaptive responses in acid excretion, but showed no significant changes in H' ATPase protein or mRNA levels in either cortex or medulla. In contrast, there were profound adaptive changes in the immunocytochemical distribution of H' ATPase in collecting duct intercalated cells. In the medulla, H' ATPase staining in acidloaded rats shifted from cytoplasmic vesicles to plasma membrane, whereas in alkali-loaded rats, cytoplasmic vesicle staining was enhanced, and staining of plasma membrane disappeared. In the cortical collecting tubule, acid loading increased the number of intercalated cells showing enhanced apical H' ATPase staining and decreased the number of cells with basolateral or poorly polarized apical staining. The results indicate that both medulla and cortex participate in the adaptive response to acid and alkali loading by changing the steady-state distribution of H' ATPase, employing mechanisms that do not necessitate postulating interconversion of intercalated cells with opposing polarities. (J. Clin. Invest. 1991. 88:126-136.)

Acid incubation reverses the polarity of intercalated cell transporters, an effect mediated by hensin

“…In six α cells examined in four CCDs, the mean alkalinization resulting from removing bath Cl -was 0.34 ± 0.02 pH units before acid incubation and 0.47 ± 0.03 pH units after acid incubation, a 36% increase (P < 0.05). These data are consistent with increased expression of apical H + -ATPase and basolateral band 3 in α cells after chronic metabolic acidosis in vivo (7,31).…”

The B1-subunit of the H+ATPase is required for maximal urinary acidification

“…5c) with the E-subunit (Fig. 5d), another subunit of the H ϩ ATPase (V1) domain known to redistribute from cytoplasmic vesicles to the apical plasma membrane of medullary ICs in response to chronic dietary acid loads (22). This B2 staining colocalized with the E-subunit in a narrow apical band at the surface of A-ICs of the IM (Fig.…”

Nongenomic stimulation of vacuolar H + -ATPases in intercalated renal tubule cells by aldosterone

“…Cells were counted as being positive either for a4 (intercalated cells) or for AQP-2 (principal cells). Intercalated cells were further classified based on the predominant subcellular distribution of a4 immunostaining as described (23,24).…”