First-generation (1-) male and female rat pups were either reared artificially on a high-carbohydrate (HC) or a high-fat (HF) formula or nursed by mother (MF) from day 4 and weaned onto a stock diet on day 24. 1-HC rats compared with sex-matched control rats (1-HF and 1-MF) were hyperinsulinemic and mildly obese by day 60. We investigated the effect of maternal hyperinsulinemia on the second generation (2-) by intragroup breeding. The 2-HC male and female rats were hyperinsulinemic on day 45, had significantly increased growth rate from approximately day 60 onward, and became obese as evidenced by increased adipose tissue mass due to hypertrophy on day 100. The lipogenic capacity of liver and adipose tissues was significantly higher in the 2-HC than in control rats. Thus the metabolic changes that occurred in the first-generation rats fed a HC formula during early postnatal life not only persisted into their adult life but were also passed on to the next generation.

We have investigated pancreatic changes associated with hyperinsulinemia and an insulin secretory response to an oral glucose load in a new rat model for obesity. Male Sprague-Dawley pups were reared on a high-carbohydrate (HC) or high-fat (HF) formula by gastrostomy during the suckling period and were weaned onto a stock diet. These animals remained either nutritionally unchallenged or challenged with a high-sucrose diet during the postweaning period. The HC formula-fed animals showed increased insulin concentrations in the plasma and pancreas and also showed impaired insulin secretory response compared with mother-fed control or HF animals in adult life. Immunocytochemical and morphometric studies revealed that hyperinsulinemia in the HC animals during the preweaning period and also in adult life was associated with hypertrophy of beta-cells in the pancreas. The results show that consumption of a HC formula during the suckling period influences pancreatic islet morphology resulting in hyperinsulinemia which eventually leads to the development of obesity later in adult life.

Results: AA diabetic women, like WA diabetic women, had a larger average very low density lipoprotein (VLDL) size, elevated levels of small low density lipoprotein cholesterol (LDL-C), and lower levels of small high density lipoprotein cholesterol (HDL-C), when compared to lean controls (p Ͻ 0.05). These differences were accompanied by higher VLDL-triglycerides (TG) and LDL-C in WA (p Ͻ 0.05), but not in AA. Although the effects of obesity and diabetes on lipoprotein subpopulation were fairly similar for AA and WA, some racial differences, particularly with respect to HDL, were observed. Discussion:The atherogenic perturbations in lipoprotein profiles of obese AA women, particularly those with diabetes, were relatively similar to those found in WA women and may be contributing to the increased rate of cardiovascular disease (CVD) in AA with obesity and diabetes. The parameters of subpopulation distribution may provide better markers for CVD than lipid concentrations alone, particularly in AA women. Furthermore, subtle racial differences in lipoprotein profiles suggest that race-specific criteria may be needed to screen patients for CVD.

Considerable evidence suggests that there are ethnic differences in lipid metabolism between African American and Caucasian women, which may result in increased synthesis of fat in adipose tissue. The purpose of this study was to measure the in vitro rates of [14C]glucose incorporation into the glyceride-glycerol backbone of triglycerides (TG) and diglycerides (DG) in abdominal subcutaneous (SAT) and omental adipose tissue (OAT). Morbidly obese [African American (n = 15): body mass index (BMI) = 45 +/- 2.3; Caucasian (n = 18): BMI = 51 +/- 2.3] and preobese [African American (n = 7): BMI = 27 +/- 1.0; Caucasian (n = 7): BMI = 25 +/- 1.0] women were examined in this study. There were no significant differences in the rates of synthesis of either TG or DG in SAT of either preobese or obese women. On the other hand, both preobese and obese African American women had higher rates of synthesis of TG in OAT compared with their Caucasian counterparts. This increase in TG synthesis in OAT was not due to differences in cell size or rates of reesterification. Thus African American woman have an increased capacity to synthesize TG in OAT compared with Caucasian women, which may contribute to the higher prevalence of obesity in African American women.