Diabetes Care, Vol 16, Issue 1 110-114, Copyright © 1993 by American Diabetes Association
The effect of glyburide on beta-cell sensitivity to glucose-dependent insulinotropic polypeptide
GS Meneilly, M Bryer-Ash and D Elahi
Department of Medicine, University of British Columbia, Vancouver, Canada.
OBJECTIVE--To assess whether treatment with glyburide alters beta-cell
sensitivity to GIP in NIDDM patients. RESEARCH DESIGN AND METHODS--We
studied 5 untreated NIDDM patients in a meal study (Ensure, 240 ml/M2) and
a 2-h hyperglycemic glucose clamp study (glucose 5.4 mM above fasting).
From 60 to 120 min of the clamp, GIP was infused in a primed continuous
manner at a rate of 2 pmol.kg-1 x min-1. Subjects then were treated with
glyburide. After they had been on a stable dose of medication for 1 mo, the
meal study and glucose clamp studies were repeated. RESULTS--In response to
treatment, a decrease in fasting glucose and an increase in weight was
observed (12.8 +/- 1.8 vs. 8.5 +/- 0.8 mM and 74.3 +/- 6.3 vs. 76.1 +/- 6.3
kg, respectively, P < 0.05). In response to the meal study, the AUC for
glucose was less, for insulin was increased, and for GIP was unchanged
after treatment (16.9 +/- 2.1 vs. 12.6 +/- 6.9 mM, P < 0.05; 161 +/- 47
vs. 242 +/- 60 pM, P < 0.05; and 199 +/- 22 vs. 219 +/- 18 pM,
respectively). During the hyperglycemic clamp, steady-state glucose and 90-
to 120-min GIP values were equivalent before and after treatment (18.0 +/-
1.3 vs. 18.3 +/- 1.3 mM and 302 +/- 59 vs. 298 +/- 37 pM, respectively).
The 90-120 min insulin responses to the hyperglycemic clamp were greater
after therapy (123 +/- 37 vs. 283 +/- 80 pM, P < 0.05) reflecting
increased beta-cell responses to GIP. CONCLUSIONS--We conclude that
glyburide enhances beta-cell sensitivity to GIP.