In a case-control study that investigated the effect of intrauterine growth
retardation (IUGR) on glucose homeostasis, 20-yr-old adults born with IUGR
were shown to be hyperinsulinemic in an oral glucose tolerance test, sugge
stive of insulin resistance. The aim of this study was to ascertain the dec
reased insulin sensitivity in young IUGR-born adults compared to that in co
ntrols. We studied 20 IUGR-born subjects and 25 controls, aged 25 yr. Insul
in sensitivity was assessed by peripheral glucose uptake and monitoring fre
e fatty acid (FFA) concentrations under euglycemic hyperinsulinemic clamp.
The percent body fat was significantly higher in the IUGR group (27.2 +/- 7
.6% us. 22.0 +/- 7.3%; P = 0.02), contrasting with comparable body mass ind
ex in both groups. Insulin-stimulated glucose uptake was significantly lowe
r in IUGR-born subjects than in controls (6.7 +/- 2.9 vs. 8.0 +/- 1.9 mg/kg
fat-free mass min; P = 0.05), and the difference remained significant afte
r adjustment for body mass index, total body fat, or waist to hip ratio. In
IUGR-born subjects, insulin-stimulated FFA suppression correlated signific
antly with peripheral glucose uptake (r(2) = 0.23; P = 0.02). First phase i
nsulin release in the iv glucose tolerance test, adjusted for insulin sensi
tivity, did not significantly differ between IUGR and control groups (442 /- 284 vs. 391 +/- 209 pmol/L; P = 0.86). In conclusion, IUGR subjects have
decreased insulin-stimulated glucose uptake as early as 25 yr of age witho
ut major impairment of insulin secretion. Low glucose uptake is associated
with a lesser degree of FFA suppression in adipose tissue, which suggests a
role of adipose tissue at an early stage of insulin resistance in these su
bjects.