Metabolic and development changes in growing rats born to dams restricted in protein and/or energy intake.

During gestation and lactation, the food intake of female rats was restricted to 50% of the ad libitum stock diet intake of controls (C). One restricted group (M1) was fed stock diet while another restricted group (M2) was fed casein-supplemented stock diet containing 66% protein. Observations were directed to their progeny. After weaning at 21 days, all progeny were fed the stock diet ad libitum for 2 weeks. Mean birth weight of M2 was lower than M1 which was lower than C. Weight gain of progeny was faster in M2 than M1 but both were less than C. At 5 weeks, M2 had normal brain weight but lower mg protein/g brain than either M1 or C. M1 had the lowest brain weight. Livers of M1 and M2 were smaller than C, and M2 had higher RNA and protein, and lower DNA per g liver than either M1 or C. Both M1 and M2 had about three-fold elevation in hepatic serine dehydratase and slightly lower phosphoglycerate dehydrogenase than C. The lower birth weight and normal brain size of M2 suggested that some of the protein consumed by M2 dams was conserved for synthesis of vital components despite energy restriction.