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Altered glucose tolerance in rats exposed to maternal low protein diets in utero
S C Langley1, R F Browne, A A Jackson
1Department of Human Nutrition, University of Southampton, U.K.
Insights
Maternal low protein diets during pregnancy alter offspring glucose metabolism. Young adult rats exposed to prenatal protein restriction show improved glucose tolerance, but this effect is not observed in older animals.
Area of Science:
- Developmental biology
- Nutritional science
- Metabolic research
Background:
- Maternal nutrition during gestation significantly impacts offspring development and long-term health.
- Prenatal exposure to dietary factors can influence metabolic programming, affecting susceptibility to diseases like diabetes.
Purpose of the Study:
- To investigate the long-term effects of prenatal exposure to varying maternal protein diets on glucose tolerance in rats.
- To determine if maternal protein restriction during fetal development alters glucose metabolism in young adulthood and later life.
Main Methods:
- Rats were exposed prenatally to maternal diets with 18%, 12%, 9%, or 6% protein.
- Intravenous glucose tolerance tests were performed on young adult (9 weeks) and older adult (44 weeks) offspring.
- Key parameters measured included body weight, peak blood glucose, glucose clearance rate, and area under the glucose tolerance curve.
Main Results:
- Offspring exposed to 6% protein diets exhibited lower body weights.
- Young adult rats from the 6% and 9% protein groups showed enhanced glucose tolerance, with reduced peak glucose levels and smaller areas under the curve compared to controls.
- No significant differences in glucose tolerance were observed between groups at 44 weeks of age.
Conclusions:
- In utero exposure to maternal low protein diets can alter glucose tolerance in young adulthood.
- The observed effects on glucose metabolism appear to be transient, diminishing by 44 weeks of age.
- The underlying mechanisms for this altered glucose tolerance due to prenatal protein restriction remain to be elucidated.
Abstract:
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.