title: Release of natriuretic factor from rat heart-lung preparation by atrial distension.
abstract: The hypothesis that an increase in blood volume results in the release of an atrial natriuretic factor (ANF) via atrial stretch was examined using an isolated rat heart-lung preparation. The heart lung preparation was perfused with a fluorocarbon emulsion for two periods of 20 min. During the first period the venous return reservoir was placed at a level of 1-2 cm above the right atrium [low central venous pressure (low CVP)] and at a level 7-12 cm above the heart (high CVP) for the second period. The perfusate used for each period was collected and saved for later analysis of natriuretic activity using anesthetized rats as a bioassay. Samples of either low or high CVP perfusate were infused into the abdominal aorta of the assay rats while urine was collected from a bladder catheter. A 3-min infusion of the high CVP perfusate at a rate of 0.5 ml/min resulted in an increase in urine flow from 10 to 28 microliter/min (P less than 0.01), sodium excretion from 0.14 to 1.34 mueq/min (P less than 0.01), and potassium excretion from 0.17 to 0.81 mueq/min (P less than 0.01). Infusion of the low CVP perfusate failed to produce a significant diuresis, natriuresis, or kaliuresis. These results are consistent with the hypothesis that ANF may be a hormone involved in the control of blood volume.
mesh_terms: D000818:Animals; D001810:Blood Volume; D002496:Central Venous Pressure; D004231:Diuresis; D006321:Heart / Q000502:physiology*; D006325:Heart Atria; D066298:In Vitro Techniques; D008168:Lung / Q000378:metabolism*; D008297:Male; D009206:Myocardium / Q000378:metabolism*; D009318:Natriuresis; D045283:Natriuretic Agents; D010477:Perfusion; D011188:Potassium / Q000652:urine; D011506:Proteins / Q000378:metabolism*; D051381:Rats; D011919:Rats, Inbred Strains
chemical_list: D045283:Natriuretic Agents; D011506:Proteins; D011188:Potassium