Regulation of epithelial Na+ channel (ENaC) in the salivary cell line SMG-C6

Margarita M. Vasquez, Shamimunisa B. Mustafa, Ahsan Choudary, Steve R. Seidner, Robert Castro

Research output: Contribution to journalArticlepeer-review

10 Scopus citations


Glucocorticoids and mineralocorticoids modulate Na+ transport via epithelial Na+ channels (ENaC). The rat submandibular epithelial cell line, SMG-C6, expresses α-ENaC mRNA and protein and exhibits amiloride-sensitive Na+ transport when grown in low-serum (2.5%) defined medium, therefore, we examined the effects of altering the composition of the SMG-C6 cell growth medium on ENaC expression and function. No differences in basal or amiloride-sensitive short-circuit current (Isc) were measured across SMG-C6 monolayers grown in the absence of thyroid hormone, insulin, transferrin, or EGF. In the absence of hydrocortisone, basal and amiloride-sensitive Isc significantly decreased. Similarly, monolayers grown in 10% serum-supplemented medium had lower basal Isc and no response to amiloride. Adding hydrocortisone (1.1 μM) to either the low or 10% serum medium increased basal and amiloride-sensitive Isc, which was blocked by RU486, the glucocorticoid and progesterone receptor antagonist. Aldosterone also induced an increase in α-ENaC expression and Na+ transport, which was also blocked by RU486 but not by the mineralocorticoid receptor antagonist spironolactone. Thus, in the SMG-C6 cell line, hydrocortisone and aldosterone increased ENaC expression and basal epithelial Na+ transport. The absence of endogenous ENaC expression in culture conditions devoid of steroids makes the properties of this cell line an excellent model for investigating pathways regulating ENaC expression and Na+ transport.

Original languageEnglish (US)
Pages (from-to)522-531
Number of pages10
JournalExperimental Biology and Medicine
Issue number5
StatePublished - May 2009


  • Amiloride
  • ENaC
  • SMG-C6 cells
  • Short-circuit current

ASJC Scopus subject areas

  • Biochemistry, Genetics and Molecular Biology(all)


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