CLCA1 and hyperinsulinemic hypoglycemia, familial, 4: In aging mice, increased renal cortical CLCA1 content was associated with hydrogen sulfide (H2S) deficiency, which was ameliorated by administering sodium hydrosulfide (NaHS), a source of H2S. In order to study whether increased CLCA1 expression leads to injury phenotype and the mechanisms involved, stable transfection of proximal tubule epithelial cells overexpressing human CLCA1 (hCLCA1) was performed.