In response to i.v. ANF at 175 ng/kg/min, normal dogs increase sodium excretion ($ Delta$UNaV = 150 uEq/min) independent of changes in GFR and RPF. In contrast, when ANF was infused into chronic caval dogs (TIVC) or cirrhotic dogs (Cir) retaining sodium in the presence of ascites, they divided 50:50 into those who had a marked natriuretic response (responders, R) and those who had no natriuretic response (non-responders, NR). Of 46 TIVC dogs, 22 R had UnaV of 185 + 35 uEq/min and 24 NR had $ Delta$UNaV = 2 + 1 uEq/min. In 19 Cir dogs, 9 R had $ Delta$UNaV = 60 + 10 uEq/min and 10 NR had $ Delta$UNaV = 1.3 +.6 uEq/min. R and NR could not be differentiated in terms of atrial content of ANF, plasma iANF, ANF T1/2, plasma levels of renin and aldosterone, systemic hemodynamics, plasma volume, or papillary plasma flow. All dogs generated plasma and urinary cGMP equally. Renal denervation or vasodilitation did not increase sodium excretion in response to ANF in RN. When NR dogs returned to sodium balance in the presence of ascites, the natriuretic response was restored ($ Delta$UNaV = 90-340 uEq/min) and was not different from R dogs in this phase. Cir dogs studied sequentially in the pre-ascitic phase responded normally to ANF infusion when they were in sodium balance but split 50:50 into R and NR at week 4 during a period of sodium retention, plasma volume expansion, elevated plasma iANF and normal renin and aldosterone. We conclude that the blunting of UNaV in response to ANF is a characteristic of the sodium-retaining kidney, is reversible when sodium balance is restored and occurs at a tubular level, most likely in the medulla.
| Identifer | oai:union.ndltd.org:LACETR/oai:collectionscanada.gc.ca:QMM.75880 |
| Date | January 1988 |
| Creators | Maher, Elizabeth Anne |
| Publisher | McGill University |
| Source Sets | Library and Archives Canada ETDs Repository / Centre d'archives des thèses électroniques de Bibliothèque et Archives Canada |
| Language | English |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Format | application/pdf |
| Coverage | Doctor of Philosophy (Department of Physiology.) |
| Rights | All items in eScholarship@McGill are protected by copyright with all rights reserved unless otherwise indicated. |
| Relation | alephsysno: 000912532, proquestno: AAINL52186, Theses scanned by UMI/ProQuest. |
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