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RENAL EFFECTS OF ATRIAL NATRIURETIC FACTOR (99–126) IN CONSCIOUS SODIUM‐REPLETE SHEEP
Author(s) -
Yates Neale A.,
McDougall John G.,
Coghlan John P.,
Coker Andrew R.,
Gibson Angela P.,
Scoggins Bruce A.
Publication year - 1988
Publication title -
clinical and experimental pharmacology and physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.752
H-Index - 103
eISSN - 1440-1681
pISSN - 0305-1870
DOI - 10.1111/j.1440-1681.1988.tb01113.x
Subject(s) - excretion , medicine , endocrinology , effective renal plasma flow , renal function , chemistry , renal physiology , fractional excretion of sodium , kidney , aldosterone , renal blood flow
SUMMARY 1. The effect of renal arterial infusion of synthetic human atrial natriuretic factor (ANF(99–126)) on renal function in the conscious euvolaemic sheep was characterized. ANF (99–126) was infused for 2 h at 5 and 50 μg/h into the renal artery of crossbred Merino ewes with chronically indwelling cannulae inserted in the renal artery. The effect on absolute and fractional excretion of Na, K, Ca, Cl and HCO 3 , glomerular filtration rate (GFR), effective renal plasma flow (ERPF) and free water clearance (C H2O ) were measured. 2. Infusion at 50 μg/h produced a fourfold increase in Na and Cl excretion. Ca excretion increased eightfold, while K and HCO 3 increased by small amounts. At the lower dose only Na, Cl and Ca excretion increased significantly. The changes in absolute excretion of each ion were closely mirrored by changes in fractional excretion. C H2O became more negative at both levels of infusion. Small changes in GFR were measured at both rates of infusion. No changes in ERPF or renin secretion were observed. 3. ANF (99–126) infusion at 50 μg/h for 1 h increased the excretion of Li, such that more than 70% of the change in Na excretion was associated with the changes in Li clearance. Changes in GFR accounted for less than 10% of change in Na excretion. 4. Following either long‐term (50 μg/h for 6 h) or repeated short‐term (20 μg/h for 30 min) infusions of ANF (99–126), the response of Na excretion was not sustained. The mechanisms of the tachyphylaxis remains undetermined. 5. ANF (99–126) is a powerful stimulus to the absolute and fractional excretion of Na, K, Ca, Cl and HCO 3 . The mechanism of action is not known, but appears to be related to changes in tubular function and/or a change in glomerulotubular balance.