Referenced in: none

Automatically associated channels: ClC4 , ClCK1 , Kir6.2

Title: Developmental expression of CLC-K1 in the postnatal rat kidney.

Authors: K Kobayashi, S Uchida, S Mizutani, S Sasaki, F Marumo

Journal, date & volume: Histochem. Cell Biol., 2001 Jul , 116, 49-56

PubMed link: http://www.ncbi.nlm.nih.gov/pubmed/11479722

Abstract
CLC-K1, a kidney-specific chloride channel, has been demonstrated to be involved in the urine concentration mechanism. Here, we investigated the developmental expression of CLC-K1 in the rat kidney. Using immunohistochemistry, we showed that CLC-K1 was not present in the thin ascending limb of Henle's loop during the early prenatal stages but was significantly expressed during the adult stage. CLC-K1 started to appear at day 5 and its expression increased during further development. In developing rats this increase coincided with the increase in the urine-concentrating capacity as the animals matured. We also investigated the expressions of other channels and transporters, including NKCC2, AQP-1, and AQP-2. NKCC2 was strongly expressed throughout the inner medulla in neonatal rat kidneys but was entirely undetectable at the adult stage. The decline in its expression took the form of a gradual recession from the inner medulla together with reciprocal increases in the expression of CLC-K1. AQP-1 was weakly expressed in the inner medulla during early development and showed a rapid increase in expression at a later stage. The collecting duct cells significantly expressed AQP-2 even at birth and maintained its expression throughout the development. These results suggest that CLC-K1 expression is one of the major determinants of the urine-concentrating capacity of the developing rat kidney.