Does atrial natriuretic factor protect against right ventricular overload? II. Tissue binding.
Previous studies have led us to hypothesize that the physiological significance of the diuretic and pulmonary vaso-relaxant effects of atrial natriuretic factor (ANF) is to protect the right heart. This study was designed to evaluate the relative importance of various peripheral tissues as sites of ANF action by tracing the temporal pattern of distribution of 125I-ANF and quantitating the specific binding sites. An in vivo approach, utilizing trace amount of 125I-ANF was adopted to simulate physiological conditions. 125I-ANF injected either intravenously or intra-arterially was quickly bound to peripheral tissues with less than 5% remaining in the circulation after 1 min. The relative binding capacity was greatest in the lung, followed by the kidney, right ventricle, adrenal gland, and left ventricle. The magnitude of specific ANF binding sites per gram of tissue weight followed a similar order. The data demonstrate that ANF released under all circumstances is quickly bound to the target organs, particularly the lung and the kidney, and suggest that these two organs could be the most important target organs of ANF. This evidence provides further support for the proposed hypothesis that a major evolutionary role of ANF is the protection of the right ventricle from mechanical loads.
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Department of Physiology, Dartmouth Medical School, Hanover, New Hampshire 03756.
Yen
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Sardella
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Hill
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D000311:Adrenal Glands / Q000378:metabolism; D000818:Animals; D009320:Atrial Natriuretic Factor / Q000378:metabolism* / Q000493:pharmacokinetics; D001665:Binding Sites; D006321:Heart / Q000502:physiology*; D007457:Iodine Radioisotopes; D007668:Kidney / Q000378:metabolism; D008168:Lung / Q000378:metabolism; D008297:Male; D051381:Rats; D011919:Rats, Inbred Strains; D014018:Tissue Distribution; D016276:Ventricular Function
D007457:Iodine Radioisotopes; D009320:Atrial Natriuretic Factor