Renal sodium handling and haemodynamics are equally affected by hyperinsulinaemia in salt-sensitive and salt-resistant hypertensives

Jan C. Ter Maaten*, Stephan J.L. Bakker, Erik H. Serné, Ab J.M. Donker, Rijk O.B. Gans

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review

Abstract

Objective. It is well-known that insulin induces renal sodium retention. It is not yet known whether insulin's renal effects are involved in the development of salt-sensitive hypertension. We assessed the effects of insulin on renal sodium handling and haemodynamics in 10 salt-sensitive (SS) and 10 salt-resistant (SR) essential hypertensives. Design. After a baseline period of 90 min, all subjects underwent a euglycaemic clamp with sequential infusion of a physiological and supraphysiological dose of insulin (50 and 150 mU/kg per h) during 90 min periods each. Time-control studies were performed in the same subjects. Clearances of 131l-hippuran, 125l-iothalamate, sodium and lithium were used to evaluate renal plasma flow (RPF), C Na/glomerular filtration rate (GFR) and fractional proximal and distal sodium reabsorption. Results. Plasma insulin levels and insulin-mediated glucose uptake did not differ between both groups. RPF and GFR showed similar increases during both insulin infusions in both groups. During physiological hyperinsulinaemia, fractional sodium excretion decreased 38% (P = 0.009) in the SS group and 36% (P = 0.002) in the SR group. During supraphysiological hyperinsulinaemia, fractional sodium excretion decreased 49% (P = 0.01) in the SS group and 19% (P = 0.2) in the SR group, not statistically different between both groups. Fractional proximal sodium reabsorption was unaffected and fractional distal sodium reabsorption increased to a similar magnitude in both groups. Conclusion. The comparable renal effects of acute exogenous hyperinsulinaemia in SS and SR hypertensives do not support a role for insulin in the development of salt-sensitive hypertension. However, the results do not yet exclude a role for chronic hyperinsulinaemia.

Original languageEnglish
Pages (from-to)1633-1641
Number of pages9
JournalJournal of Hypertension
Volume19
Issue number9
DOIs
Publication statusPublished - 5 Sep 2001

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