ECE1 and hyperinsulinism: Similarly, ECE protein, which is responsible for cleaving inactive proendothelin to the active endothelin‐1 peptide, was upregulated in response to hyperinsulinemia in LHCs (basal: 0.80 ± 0.06; insulin: 1.08 ± 0.17, P = 0.02); however, no significant changes were detected in T2DM subjects.