Prazosin blunts the antinatriuretic effect of circulating angiotensin II in man

Chim C. Lang, Abdul R. Rahman, David J.K. Balfour, Allan D. Struthers

    Research output: Contribution to journalArticle

    9 Citations (Scopus)

    Abstract

    OBJECTIVE:
    The present study examines the role of alpha 1-adrenoceptors in determining the renal haemodynamic and sodium excretory responses to a physiological dose of angiotensin II in man.
    DESIGN:
    The effects of a low-dose infusion of angiotensin II (1 ng/kg per min) and a non-depressor dose of prazosin (0.25 mg), alone and in combination, on urinary sodium excretion (UlslaV), effective renal plasma flow (ERPF), glomerular filtration rate (GFR) and segmental tubular function were studied in eight normal male subjects.
    METHODS:
    Subjects were studied undergoing maximal water diuresis. Clearances of inulin and para-aminohippurate were employed to estimate GFR and ERPF, respectively. Segmental tubular handling was assessed by both lithium clearance (CLi) and solute-free water methods.
    RESULTS:
    Angiotensin II decreased UNaV without altering ERPF and GFR. Angiotensin II caused a significant fall in fractional CLi, which may indicate a proximal tubular effect of angiotensin II. Angiotensin II alone also increased fractional reabsorption of sodium delivered to the distal nephron, as evaluated by both the CLi method and by estimation of solute-free water clearance. When angiotensin II was given in combination with prazosin, which on its own had no apparent effects on any renal parameters, the antinatriuretic and tubular effects of angiotensin II were significantly blunted.
    CONCLUSIONS:
    These findings suggest that low doses of circulating angiotensin II are able to modulate UNaV by increasing sodium reabsorption in the proximal and, to some extent, the distal nephron segment in man. The study also showed that a non-depressor dose of prazosin blunted the renal effects of angiotensin II, thereby providing tentative evidence of a renal interaction between alpha-adrenoceptors and angiotensin II in man.
    Original languageEnglish
    Pages (from-to)1387-1395
    Number of pages9
    JournalJournal of Hypertension
    Volume10
    Issue number11
    Publication statusPublished - Nov 1992

    Fingerprint

    Prazosin
    Angiotensin II
    Effective Renal Plasma Flow
    Sodium
    Glomerular Filtration Rate
    Kidney
    Nephrons
    Adrenergic Receptors
    Water
    Inulin
    Diuresis
    Lithium
    Hemodynamics

    Cite this

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    title = "Prazosin blunts the antinatriuretic effect of circulating angiotensin II in man",
    abstract = "OBJECTIVE:The present study examines the role of alpha 1-adrenoceptors in determining the renal haemodynamic and sodium excretory responses to a physiological dose of angiotensin II in man.DESIGN:The effects of a low-dose infusion of angiotensin II (1 ng/kg per min) and a non-depressor dose of prazosin (0.25 mg), alone and in combination, on urinary sodium excretion (UlslaV), effective renal plasma flow (ERPF), glomerular filtration rate (GFR) and segmental tubular function were studied in eight normal male subjects.METHODS:Subjects were studied undergoing maximal water diuresis. Clearances of inulin and para-aminohippurate were employed to estimate GFR and ERPF, respectively. Segmental tubular handling was assessed by both lithium clearance (CLi) and solute-free water methods.RESULTS:Angiotensin II decreased UNaV without altering ERPF and GFR. Angiotensin II caused a significant fall in fractional CLi, which may indicate a proximal tubular effect of angiotensin II. Angiotensin II alone also increased fractional reabsorption of sodium delivered to the distal nephron, as evaluated by both the CLi method and by estimation of solute-free water clearance. When angiotensin II was given in combination with prazosin, which on its own had no apparent effects on any renal parameters, the antinatriuretic and tubular effects of angiotensin II were significantly blunted.CONCLUSIONS:These findings suggest that low doses of circulating angiotensin II are able to modulate UNaV by increasing sodium reabsorption in the proximal and, to some extent, the distal nephron segment in man. The study also showed that a non-depressor dose of prazosin blunted the renal effects of angiotensin II, thereby providing tentative evidence of a renal interaction between alpha-adrenoceptors and angiotensin II in man.",
    author = "Lang, {Chim C.} and Rahman, {Abdul R.} and Balfour, {David J.K.} and Struthers, {Allan D.}",
    year = "1992",
    month = "11",
    language = "English",
    volume = "10",
    pages = "1387--1395",
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    issn = "0263-6352",
    publisher = "Lippincott Williams and Wilkins",
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    }

    Prazosin blunts the antinatriuretic effect of circulating angiotensin II in man. / Lang, Chim C.; Rahman, Abdul R.; Balfour, David J.K.; Struthers, Allan D.

    In: Journal of Hypertension, Vol. 10, No. 11, 11.1992, p. 1387-1395.

    Research output: Contribution to journalArticle

    TY - JOUR

    T1 - Prazosin blunts the antinatriuretic effect of circulating angiotensin II in man

    AU - Lang, Chim C.

    AU - Rahman, Abdul R.

    AU - Balfour, David J.K.

    AU - Struthers, Allan D.

    PY - 1992/11

    Y1 - 1992/11

    N2 - OBJECTIVE:The present study examines the role of alpha 1-adrenoceptors in determining the renal haemodynamic and sodium excretory responses to a physiological dose of angiotensin II in man.DESIGN:The effects of a low-dose infusion of angiotensin II (1 ng/kg per min) and a non-depressor dose of prazosin (0.25 mg), alone and in combination, on urinary sodium excretion (UlslaV), effective renal plasma flow (ERPF), glomerular filtration rate (GFR) and segmental tubular function were studied in eight normal male subjects.METHODS:Subjects were studied undergoing maximal water diuresis. Clearances of inulin and para-aminohippurate were employed to estimate GFR and ERPF, respectively. Segmental tubular handling was assessed by both lithium clearance (CLi) and solute-free water methods.RESULTS:Angiotensin II decreased UNaV without altering ERPF and GFR. Angiotensin II caused a significant fall in fractional CLi, which may indicate a proximal tubular effect of angiotensin II. Angiotensin II alone also increased fractional reabsorption of sodium delivered to the distal nephron, as evaluated by both the CLi method and by estimation of solute-free water clearance. When angiotensin II was given in combination with prazosin, which on its own had no apparent effects on any renal parameters, the antinatriuretic and tubular effects of angiotensin II were significantly blunted.CONCLUSIONS:These findings suggest that low doses of circulating angiotensin II are able to modulate UNaV by increasing sodium reabsorption in the proximal and, to some extent, the distal nephron segment in man. The study also showed that a non-depressor dose of prazosin blunted the renal effects of angiotensin II, thereby providing tentative evidence of a renal interaction between alpha-adrenoceptors and angiotensin II in man.

    AB - OBJECTIVE:The present study examines the role of alpha 1-adrenoceptors in determining the renal haemodynamic and sodium excretory responses to a physiological dose of angiotensin II in man.DESIGN:The effects of a low-dose infusion of angiotensin II (1 ng/kg per min) and a non-depressor dose of prazosin (0.25 mg), alone and in combination, on urinary sodium excretion (UlslaV), effective renal plasma flow (ERPF), glomerular filtration rate (GFR) and segmental tubular function were studied in eight normal male subjects.METHODS:Subjects were studied undergoing maximal water diuresis. Clearances of inulin and para-aminohippurate were employed to estimate GFR and ERPF, respectively. Segmental tubular handling was assessed by both lithium clearance (CLi) and solute-free water methods.RESULTS:Angiotensin II decreased UNaV without altering ERPF and GFR. Angiotensin II caused a significant fall in fractional CLi, which may indicate a proximal tubular effect of angiotensin II. Angiotensin II alone also increased fractional reabsorption of sodium delivered to the distal nephron, as evaluated by both the CLi method and by estimation of solute-free water clearance. When angiotensin II was given in combination with prazosin, which on its own had no apparent effects on any renal parameters, the antinatriuretic and tubular effects of angiotensin II were significantly blunted.CONCLUSIONS:These findings suggest that low doses of circulating angiotensin II are able to modulate UNaV by increasing sodium reabsorption in the proximal and, to some extent, the distal nephron segment in man. The study also showed that a non-depressor dose of prazosin blunted the renal effects of angiotensin II, thereby providing tentative evidence of a renal interaction between alpha-adrenoceptors and angiotensin II in man.

    M3 - Article

    VL - 10

    SP - 1387

    EP - 1395

    JO - Journal of Hypertension

    JF - Journal of Hypertension

    SN - 0263-6352

    IS - 11

    ER -