Functional Profile of the Isolated Uremic Nephron: IMPAIRED WATER PERMEABILITY AND ADENYLATE CYCLASE RESPONSIVENESS OF THE CORTICAL COLLECTING TUBULE TO VASOPRESSIN
AUTOR(ES)
Fine, Leon G.
RESUMO
Resistance of the chronically diseased kidney to vasopressin has been proposed as a possible explanation for the urinary concentrating defect of uremia. The present studies examined the water permeability and adenylate cyclase responsiveness of isolated cortical collecting tubules (CCT) from remnant kidneys of uremic rabbits to vasopressin. In the absence of vasopressin the CCTs of both normal and uremic rabbits were impermeable to water. At the same osmotic gradient, addition of a supramaximal concentration of vasopressin to the peritubular bathing medium led to a significantly lower net water flux per unit length (and per unit luminal surface area) in uremic CCTs than in normal CCTs. Transepithelial osmotic water permeability coefficient, Pf, was 0.0232 ±0.0043 cm/s in normal CCTs and 0.0059±0.001 cm/s in uremic CCTs (P < 0.001). The impaired vasopressin responsiveness of the uremic CCTs was observed whether normal or uremic serum was present in the bath.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=372678Documentos Relacionados
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