passages.id: split_8_test_1527_passage
passages.type: progene_text
passages.text: Peptide bioavailability and potency can be regulated through hypoxic up - and down - regulation of synthesis or release , activation by converting enzymes ( ACE for AII and ECE for ET-1 ) , inactivation by neutral endopeptidase and proteases , or by interaction with nitric oxide ( NO ) .