Diabetes in pregnancy is associated with an increased risk of obesity and glucose intolerance in children and the development of non-insulin dependent diabetes (NIDDM) in young adults. Genetic predisposition may be one factor leading to this increased risk. However, we suggest that an abnormal metabolic intrauterine milieu alone can predispose offspring to develop glucose intolerance. We have developed a rat model of fetal overgrowth (LGA) and mild fetal hyperglycemia and hyperinsulinemia. Maternal rats are not diabetic. We hypothesized that fetuses exposed to this abnormal intrauterine metabolic milieu would develop glucose intolerance as juvenile pups. In addition, as aberrant hepatic metabolism is a feature of NIDDM, we hypothesized that key components of hepatic metabolism such as glucose transport and glucose phosphorylation would be altered in LGA rat pups. We performed selective ablation of alternate fetuses by uterine artery branch ligation on gestational day 15 (term=21.5)(n=15); litters from sham operated mothers served as controls (C) (n=12). Fetuses were allowed to deliver spontaneously. OGTT's, glucokinase and hexokinase activity, and GLUT 2 protein and mRNA, levels were determined in liver of 21d animals. Body, but not liver weights were higher in LGA animals compared to C (Body: 63.39±1.22 v. 52.3±1.64 g; Liver: 2.07±0.17 v.2.09±0.13 g, LGA vs C, respectively)(p<0.05). Basal glucose (10.91 ±1.11 v 11.79±1.2 mM, LGA v C) and insulin (1.79±0.75 v 1.90±0.63 ng/mL, LGA v C) levels were similar in LGA and C. However, after glucose loading, glucose(19.27±2.1 v 14.47±1.8 mM LGA v C) and insulin levels(4.92±0.45 v 3.00±0.21 ng/mL, LGA v C) were higher in LGA compared to C at 1h (p<0.05). Glucokinase activity was lower in LGA liver(10.09±0.54mU/mg protein/min) compared to C (16.99±0.65 mU/mg protein/min), (p<0.05). LGA Glut 2 protein and mRNA levels were also less than C (45% of C for protein and 20% of C for mRNA) (p<0.01). Immunohistochemistry demonstrated that the intensity of staining for Glut 2 was qualitatively less in LGA liver. In summary, LGA pups had increased body weight, glucose intolerance, decreased hepatic GLUT 2 expression, and decreased hepatic glucokinase activity. Decreased glucokinase activity results in an inability of glucose to suppress hepatic glucose production, and its impairment may contribute to the glucose intolerance observed in these animals. The physiologic consequence of diminished hepatic GLUT 2 levels is unclear. Our results support the hypothesis that transient fetal hyperglycemia and hyperinsulinemia can cause permanent metabolic imprinting after birth.