Horm Metab Res 2009; 41(8): 600-604
DOI: 10.1055/s-0029-1220723
Original Basic

© Georg Thieme Verlag KG Stuttgart · New York

Renal Glucose Excretion and Tubular Reabsorption Rate Related to Blood Glucose in Subjects with Type 2 Diabetes with a Critical Reappraisal of the “Renal Glucose Threshold” Model

S. Wolf 1 , K. Rave 1 , L. Heinemann 1 , K. Roggen 1
  • 1Profil Institut für Stoffwechselforschung GmbH, Neuss, Germany
Further Information

Publication History

received 02.02.2009

accepted 31.03.2009

Publication Date:
05 May 2009 (eFirst)

Abstract

Until today a “renal threshold for glucose” is described in most medical textbooks. Notwithstanding, low glucose levels are detectable in urine even under euglycaemic conditions – a phenomenon which was observed already in 1904 and labelled as “basal glucosuria”. We aimed to characterise renal glucose transport during various steady-state blood glucose levels. Twenty-two subjects with type 2 diabetes and normal renal function underwent two 5-period hyperglycaemic glucose-clamps with blood glucose target levels between 7.8 and 13.3 mmol·l−1. A virtual renal threshold for glucose excretion (VRTG) was calculated for every subject as the highest blood glucose concentration during the glucose-clamps associated with a concomitant urinary glucose level of <2.8 mmol·l−1. VRTG of subjects was classified as low, medium, and high. Each urine sample contained a detectable amount of glucose with a minimal urinary glucose concentration of 0.73 mmol·l−1. Median VRTG was 11.0 mmol·l−1, ranging from 7.8 and 12.1 mmol·l−1. With increasing blood glucose renal glucose excretion increased in each subject – but varied considerably between subjects. For example, at a blood glucose concentration of 11 mmol·l−1 renal glucose excretion ranged from 163 μmol·min−1 to 25 μmol·min−1 in subjects exhibiting a low to high VRTG, thus showing a variability >factor 6. This study reinforces the rejection of the concept of a renal threshold for glucose. Instead, this study shows a substantial variability of renal glucose excretion between subjects with type 2 diabetes.

References

Correspondence

K. Rave, MD 

Profil Institut für Stoffwechselforschung GmbH

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41460 Neuss

Germany

Phone: +49/2131/40 18 403

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Email: klaus.rave@profil-research.de