DIABETES, VOLUME 45, SUPPLEMENT 1, JANUARY 1996, PAGES S66-S69
Insulin-Induced Glucose Transporter (GLUT1 and GLUT4)
Translocation in Cardiac Muscle Tissue Is Mimicked by Bradykinin
K. Rett, M. Wicklmayr, G. J. Dietze, and H. U. Haring
The effect of bradykinin on glucose transporter translocation in isolated rat heart was compared with the effect of
insulin. Hearts from male obese (fa/fa) Zucker rats were perfused under normoxic conditions and constant
pressure in a classic Langendorff preparation with 12 mmol/1 glucose as substrate, and a set of functional
parameters was measured simultaneously. Bradykinin was administered at a concentration (10-11 mmol/1) that
did not increase coronary flow. Insulin was used at a concentration (8 x 10-8 mmol/1) known to maximally
stimulate glucose transport in this model. After 15 min of perfusion with insulin or bradykinin, subcellular
membrane fractions of the heart were prepared, and distribution of glucose transporter protein (GLUT1 and
GLUT4) in fractions enriched with surface membranes (transverse tubules [TTs] and sarcolemmal membranes
[PMs]) and with low-density microsomal membranes (LDMs) were determined by immunoblotting with the
respective antibodies. Both glucose transporter isoforms were translocated after stimulation with insulin
(increased transporter protein content in the PM+TT-enriched fraction with a concomitant decrease in the
LDM-enriched fraction) and, to a smaller extent, also with bradyknun. These data suggest that in hearts of
insulinresistant obese (falfa ) Zucker rats, bradykinin interacts with or facilitates the translocation process of
both GLUT1 and GLUT4. Diabetes 45 (Suppl. 1):S66-S69, 1996
Copyright © 1996 American Diabetes Association
Last updated: 5/30/96
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