Glucose Levels at the Site of Subcutaneous Insulin Administration and Their Relationship to Plasma Levels

  1. Stefan Lindpointner, MD1,
  2. Stefan Korsatko, MD1,
  3. Gerd Köhler, MD1,
  4. Hans Köhler, MSC2,
  5. Roland Schaller, MSC2,
  6. Lukas Schaupp, PHD1,2,
  7. Martin Ellmerer, PHD1,
  8. Thomas R Pieber, MD1,2 and
  9. Werner Regittnig, PHD (werner.regittnig{at}healthsite.at)1
  1. 1Department of Internal Medicine, Division of Endocrinology and Nuclear Medicine, Medical University of Graz, Auenbruggerplatz 15, A-8036, Graz, Austria
  2. 2Institute of Medical Technologies and Health Management, Joanneum Research Forschungsgesellschaft mbH, Elisabethstrasse 11a, A-8010 Graz, Austria

Abstract

Objective: To examine insulin's effect on the tissue glucose concentration at the site of subcutaneous insulin administration.

Research Design And Methods: A CMA-60 microdialysis (MD) catheter and a 24-gauge microperfusion (MP) catheter were inserted into the subcutaneous adipose tissue of fasting, healthy subjects (n=5). Both catheters were perfused with regular human insulin (100 U/ml) over a 6-h period, and used for glucose sampling and simultaneous administration of insulin at sequential rates of 0.33, 0.66, and 1.00 U/h (each rate was used for 2h). Before and after the insulin delivery period, both catheters were perfused with an insulin-free solution (5%-mannitol) for 2h, and used for glucose sampling only. Blood plasma glucose was clamped at euglycemic levels during insulin delivery.

Results: Start of insulin delivery with MD and MP catheters resulted in a decline of the tissue glucose concentration and the tissue-to-plasma glucose ratio for ∼60 min (p<0.05). However, during the rest of the 6-h period of variable insulin delivery, tissue glucose concentration paralleled the plasma glucose concentration and the tissue-to-plasma glucose ratio for MD and MP catheters remained unchanged at 83.2 ± 3.1 and 77.1 ± 4.8 %, respectively. After subsequent switch to insulin-free perfusate, tissue glucose concentration and tissue-to-plasma glucose ratio increased slowly and re-attained pre-insulin-delivery levels by the end of the experiments.

Conclusions: The results show the attainment of a stable tissue-to-plasma glucose ratio at the site of insulin administration, thus indicating that insulin delivery and glucose sensing may be performed simultaneously at the same adipose tissue site.

Footnotes

    • Received August 16, 2009.
    • Accepted January 14, 2010.

This Article

  1. Diabetes Care
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