BOTH A REDUCED ACUTE INSULIN-RESPONSE TO GLUCOSE AND LOWER GLUCOSE EFFECTIVENESS ARE RESPONSIBLE FOR THE WORSENING OF INTRAVENOUS GLUCOSE-TOLERANCE IN HEALTHY-SUBJECTS INDEPENDENTLY OF THE DEGREE OF OBESITY
D. Araujovilar et al., BOTH A REDUCED ACUTE INSULIN-RESPONSE TO GLUCOSE AND LOWER GLUCOSE EFFECTIVENESS ARE RESPONSIBLE FOR THE WORSENING OF INTRAVENOUS GLUCOSE-TOLERANCE IN HEALTHY-SUBJECTS INDEPENDENTLY OF THE DEGREE OF OBESITY, Metabolism, clinical and experimental, 47(3), 1998, pp. 313-320
The effects of the acute insulin response to glucose (AIRS), insulin s
ensitivity (S-I), and glucose effectiveness at zero insulin (GEZI) on
intravenous glucose tolerance were studied in 94 non elderly healthy s
ubjects with a wide range of body mass index (BMI). Conrad's coefficie
nt of glucose assimilation (K-G) was calculated between 10 and 19 minu
tes of an intravenous glucose tolerance test. Both S-I and GEZI were e
stimated using Bergman's minimal model. AIRS was calculated as the are
a under the insulin curve above basal between 0 and 10 minutes, and th
e suprabasal insulin effect was determined by the product of S-I x AIR
S. Stepwise multiple regression showed that the combined effect of S-I
x AIRg and GEZI explained 67% of the K-G index variance. Division of
the sample into tertiles according to K-G shows that subjects with the
lowest K-G (K-G < 1.32 min(-1)) had the lowest AIRg (2,832 +/- 1,362
v 6,510 +/- 4,410 [pmol.L-1] min, P = .0005), the lowest GEZI (0.092 /- 0.06 v 0.179 +/- 0.09 min(-1) P = .0004), and the lowest S-I x AIRg
(0.014 +/- 0.008 v 0.022 +/- 0.01 min(-1), P = .00001), and were the
oldest (41 +/- 10 v 31 +/- 10 years, P = .002) compared with subjects
with the highest K-G (K-G > 1.8 min(-1)). However, no differences in S
-I (4.86 +/- 4.6 v 6.5 +/- 3.7 min(-1) [pmol.L-1],(-1) NS) or BMI (29.
6 +/- 5.0 v 26.6 +/- 5.9 kg.m(-2), NS) were observed. These results di
d not vary when lean and obese subjects were analyzed separately. Age
correlated significantly only with S-I x AIRg. In conclusion, although
the main factors that determine intravenous glucose tolerance are the
suprabasal insulin effect and GEZI, worsening of the K-G index depend
s on inadequate insulin secretion for the degree of insulin sensitivit
y and lower non-insulin-mediated glucose uptake, Age seems to be anoth
er factor in the worsening of intravenous glucose tolerance through a
lower suprabasal insulin effect. Copyright (C) 1998 by W.B. Saunders C
ompany.