Altered glucose tolerance in rats exposed to maternal low protein diets in utero.

The response to an intravenous glucose load was evaluated in four groups of rats following fetal exposure to maternal diets containing 18, 12, 9 or 6% protein. The animals differed nutritionally only in terms of this prenatal experience. Animals in the 6% protein exposed group exhibited lower body weights at all ages, whilst the body weights of 9 and 12% protein exposed rats did not differ from the control group. At 9 weeks of age, a 2 g/kg body weight intravenous glucose load was cleared in 60 min by 18% protein exposed, control rats and 12% protein exposed rats. Peak blood glucose concentrations in these animals were 27.2 and 27.1 mM, respectively. Rats exposed to 9% protein in utero also cleared the glucose load in 60 min, but peak blood glucose concentrations were lower (24.4 mM), and the area under the glucose tolerance curve was 28% lower than in controls. Rats in the 6% protein exposed group cleared the glucose load in 40 min and peak blood glucose levels were only 22.1 mM. The area under the glucose tolerance curve was reduced by 40% relative to controls. When the glucose tolerance test was repeated in animals aged 44 weeks, no differences in peak glucose concentrations, area under the curve or rates of glucose clearance were observed. In utero exposure of rats to maternal low protein diets has been shown, therefore, to alter glucose tolerance in young adulthood through an, as yet, undefined mechanism.