Adrenomedullin suppresses atrial natriuretic factor (ANF) secretion from isolated atrium.
Atrial natriuretic factor (ANF) secretion was studied using isolated perfused right atria prepared from rats. Adrenomedullin (ADM), a recently identified 52-amino acid peptide whose biological activity has a striking resemblance to that of ANF, was added to the perfusate at a concentration of 1 microg/ml. The concentration of ANF secreted into the perfusate was measured by radioimmunoassay, under basal conditions (atrial wall unstressed), and during atrial distention (intraluminal pressure raised to 4 and to 6 cm water). It was found that basal secretion of ANF was not altered by ADM. However, when intraluminal pressure was raised, there was a significantly smaller increase in ANF secretion in the ADM-infused atria than in the control atria. It is concluded that ADM significantly reduces stretch-induced secretion of ANF, while having only minimal effects on basal secretion. Such an inhibitory mechanism would ensure the necessary negative feedback mechanism to counter the previously-reported stimulatory actions of ANF on ADM secretion. Moreover, these results support the hypothesis that ADM could be responsible for the reduction in stretch-induced ANF release observed during pregnancy.
Kaufman
S
S
Department of Physiology, University of Alberta, Edmonton, Canada. susan.jacobs@ualberta.ca
Deng
Y
Y
D053607:Adrenomedullin; D000818:Animals; D009320:Atrial Natriuretic Factor / Q000378:metabolism*; D001794:Blood Pressure / Q000187:drug effects; D002316:Cardiotonic Agents / Q000494:pharmacology*; D006321:Heart / Q000187:drug effects*; D006325:Heart Atria / Q000187:drug effects / Q000378:metabolism; D066298:In Vitro Techniques; D008297:Male; D009206:Myocardium / Q000378:metabolism*; D010455:Peptides / Q000494:pharmacology*; D011863:Radioimmunoassay; D051381:Rats; D017207:Rats, Sprague-Dawley; D014665:Vasodilator Agents / Q000494:pharmacology*
D002316:Cardiotonic Agents; D010455:Peptides; D014665:Vasodilator Agents; D053607:Adrenomedullin; D009320:Atrial Natriuretic Factor