| First Author | Petrovic S | Year | 2002 |
| Journal | Am J Physiol Renal Physiol | Volume | 282 |
| Issue | 1 | Pages | F133-43 |
| PubMed ID | 11739121 | Mgi Jnum | J:75598 |
| Mgi Id | MGI:2177108 | Doi | 10.1152/ajprenal.00124.2001 |
| Citation | Petrovic S, et al. (2002) Novel Schering and ouabain-insensitive potassium-dependent proton secretion in the mouse cortical collecting duct. Am J Physiol Renal Physiol 282(1):F133-43 |
| abstractText | The intercalated (IC) cells of the cortical collecting duct (CCD) are important to acid-base homeostasis by secreting acid and reabsorbing bicarbonate. Acid secretion is mediated predominantly by apical membrane Schering (SCH-28080)-sensitive H(+)-K(+)- ATPase (HKA) and bafilomycin-sensitive H(+)-ATPase. The SCH-28080-sensitive HKA is believed to be the gastric HKA (HKAg). Here we examined apical membrane potassium-dependent proton secretion in IC cells of wild-type HKAg (+/+) and HKAg knockout (-/-) mice to determine relative contribution of HKAg to luminal proton secretion. The results demonstrated that HKAg (-/-) and wild-type mice had comparable rates of potassium-dependent proton secretion, with HKAg (-/-) mice having 100% of K(+)-dependent H(+) secretion vs. wild-type mice. Potassium-dependent proton secretion was resistant to ouabain and SCH-28080 in HKAg knockout mice but was sensitive to SCH-28080 in wild-type animals. Northern hybridizations did not demonstrate any upregulation of colonic HKA in HKAg knockout mice. These data indicate the presence of a previously unrecognized K(+)-dependent SCH-28080 and ouabain-insensitive proton secretory mechanism in the cortical collecting tubule that may play an important role in acid-base homeostasis. |
