Wistar rats with non-insulin dependent diabetes induced by neonatal streptozotocin (STZ) administration were raised either in large or in small litters. The STZ-treated rats from small litters showed a higher body weight as well as increased blood glucose levels compared with vehicle- and STZ-treated rats reared in large nests at an age of 8 weeks. The higher body weight of these rats was maintained until an age of 15 weeks, whereas the basal blood glucose was normalized. However, both STZ-treated groups exhibited an impaired glucose tolerance. During pregnancy only the glucose tolerance of the STZ-treated animals from large nests was improved although not normalized. The STZ-treated rats from small nests failed to adapt to pregnancy because the blood glucose levels after glucose load were similar to values found in the virgin state. The body weight of pregnant STZ treated rats raised in small litters was significantly lower than in vehicle- or STZ-terated rats from large nests. The number of fetuses per litter was similar in all groups tested. Compared with the vehicle-treated rats from large litters the fetal body weight of STZ-treated rats from small nests was decreased and that of STZ rats raised in large litters was increased. These results suggest that the rats with the more impaired glucose tolerance produce growth-retarded pups and, conversely, rats with rather mild impairment have bigger fetuses than the vehicle-treated ones. In the present study we have examined for the first time the combined effects of postnatal overnutrition and pregnancy on glucose homeostasis of rats treated neonatally with STZ. Our data demonstrate that postnatal overnutrition is an aggravating factor in the development of a diabetic state in these rats, especially at times when the insulin requirement is higher such as puberty and pregnancy.
Animal Nutritional Physiological Phenomena Animals