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Gender‐dependent regulation of expression of the KCNQ1 channel regulatory β‐subunit KCNE3 throughout the estrous cycle in rat distal colonic crypts
Author(s) -
O'Mahony Fiona,
Alzamora Rodrigo,
Carter Derek,
Thomas Warren,
Harvey Brian J.
Publication year - 2010
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.24.1_supplement.1002.14
Subject(s) - estrous cycle , endocrinology , medicine , biology , ussing chamber , potassium channel , protein subunit , secretion , sexual dimorphism , messenger rna , epithelium , gene , genetics
The KCNQ1 potassium channel associates with the KCNE3 (‐subunit in the epithelium of the colon and mediates basolateral K+ recycling that is required for apical Cl− secretion. This study tested whether sexual dimorphism exists in the expression and function of the KCNQ1/KCNE3 channel complex in rat distal colonic crypts. The association of KCNE3 with KCNQ1 and the abundance of KCNE3 mRNA and protein were significantly higher in male compared to female crypts. KCNE3 protein expression in the female rat colon varied throughout the estrous cycle; expression was highest during proestrus and declined 4.8‐fold in estrus (P (0.01, n=3) and became undetectable at metaestrus. Whole‐cell K+ currents in male crypts displayed a linear current‐voltage relationship and were 10‐fold more sensitive to chromanol 293B when compared with K+ currents in female crypts which displayed outward rectification. Basolateral membrane K+ currents recorded in colonic epithelia mounted in Ussing chambers also displayed a 10‐fold higher sensitivity to chromanol 293B in male tissues compared to females. This study demonstrates gender and estrous cycle regulation of the expression of KCNE3 and the properties of the KCNQ1 channel activity required for Cl− secretion. Funded by HEA Ireland PRTLI NBIP Cycle 4.