Effects on isolated arteries from rat, rabbit and man of NNC 70-0270, a synthetic atrial natriuretic factor analogue with a prolonged action.

A new analogue of ANF (atrial natriuretic factor), NNC 70-0270, was tested in various isolated artery preparations. In the rabbit aorta and renal artery NNC 70-0270 was compared with atriopeptin III and the relative inhibitory potency against noradrenaline-induced contractions (atriopeptin III = 1) was found to be 5 and 9, respectively. Furthermore the duration of the effect (after washout) was prolonged. In the rat aorta the relative potency was 0.5 and a prolonged effect was also found in this preparation. In the human pulmonary artery alpha-hANF was used as a reference, and contractions were induced with noradrenaline (seven experiments) or potassium chloride (three experiments). The relative (alpha-hANF = 1) inhibitory potencies were 0.8 and 1.3, respectively. A pronounced prolongation of the effect was also found in this preparation.