Developmental expression of ROMK in rat kidney
Zolotnitskaya, A.; Satlin, L.M.
American Journal of Physiology 276(6): F825-F836
1999
ISSN/ISBN: 0002-9513 PMID: 10362771 Document Number: 499616
The apical secretory K+ (SK) channel in the principal cell represents the rate-limiting step for K+ secretion across the cortical collecting duct (CCD). Patch clamp analysis of maturing rabbit principal cells identifies an increase in number of conducting SK channels after the 2nd week of life 40-kDa band, the expected size for ROMK. Immunolocalization of a-ENaC showed apical staining of a majority of cells in distal nephron segments after the 1st week of postnatal life. The b- and c-ENaC subunit expression was routinely detected in a mostly cytoplasmic distribution immediately after birth, albeit in low abundance; c-ENaC showed some apical polarization. These results suggest that the postnatal increases in a principal cell apical SK and Na+ channel activity are mediated, at least in part, by increases in abundance of ROMK message and protein and ENaC subunit proteins. Reprinted by permission of the publisher.