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EFFECT OF ATRIAL PEPTIDE ON COLLECTING DUCT FUNCTION
Author(s) -
Fitzgibbon Wayne,
Morgan Trefor
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.tb01027.x
Subject(s) - peptide , medicine , duct (anatomy) , function (biology) , cardiology , chemistry , microbiology and biotechnology , biology , anatomy , biochemistry
b 1. The effects of synthetic rat atrial natriuretic peptides (ANP) on diffusional 22 Na + , 36 Cl − and tritiated water (THO) permeability of in vitro microperfused rat papillary collecting ducts and the effect in vivo of ANP on stop‐flow sodium concentrations in the terminal segment of rabbit nephrons were studied. 2. The addition of 4 ± 10 −8 or 4 ± 10 −7 mol/l ANP to the medium or perfusion solution did not alter diffusional 22 Na + or 36 Cl − permeability of microperfused rat papillary collecting ducts. 3. The basal diffusional THO permeability of papillary collecting ducts was not altered when 4 ± 10 −7 mol/l ANP was present in the medium and did not inhibit the increment in diffusional THO permeability induced by vasopressin or reduce the permeability to water in a duct previously stimulated by vasopressin. 4. The administration of ANP (2 μg/kg bodyweight) to rabbits in water diuresis did not alter systemic blood pressure but induced a marked natriuresis and increases in urine flow and potassium excretion. This natriuresis was not associated with alterations in stop‐flow sodium reabsorptive capacity or sodium permeability of the collecting tubules and ducts. 5. Previously reported in vivo clearance data suggest that ANP causes, at least in part, a natriuresis by altering sodium transport in the medullary collecting ducts. In this study, however, a direct effect could not be demonstrated and it is possible that the medulla needs to be functioning in its normal environment for such effects to be demonstrated.