The N-terminus, C-terminus, and vessel dilator of the ANF prohormone are present in the urine and increase with ventricular fibrillation

Summary The N-terminus consisting of amino acids (a.a.) 1–98 (i.e., proANF 1–98), C-terminus (i.e., ANF; a.a. 99–126) and midportion of N-terminus consisting of a.a. 31–67 (proANF 31–67; Vessel Dilator) of the 126 a.a. ANF prohormone were present in the urine in 5-to-8-fold increased concentrations versus their plasma concentrations in 6 dogs under basal conditions. With acute coronary occlusion the right atrial plasma concentrations of these peptides increased two-to-three-fold, while in the urine only proANF 31–67 increased (3.5-fold). Ventricular fibrillation caused a 4-to-10-fold increased secretion into the right atrial chamber with a simultaneous 3-to-4.7-fold increase in the urine of proANF 1–98, proANF 31–67, and ANF. This investigation demonstrates that proANF 1–98, proANF 31–67 and ANF are normally present in urine and increase in the urine with cardiac stimuli that cause their release from the heart.