1. Investigación

To determine the effect of under-nutrition during suckling in adults, at delivery female Sprague Dawley rats were allowed to lactate litters of either eight (controls) or sixteen pups each (large litter, LL). The amount of milk taken by LL pups was less than the controls and the concentration of triacylglycerols (TG) in the milk of the former was lower. The increase of both body weight and length in LL was lower than in the controls during suckling. At weaning, pups were allowed to eat ad libitum a standard diet and whereas at 20 months female body weight did not differ between LL and control rats, LL males weighed less than controls. Plasma NEPA were lower in male LL than in controls at 10 months, leptin at 10 and 16 months and TG and VLDL-TG at 20 months, with no differences in females. When 20 months old, lumbar and epididymal adipose tissue weights were lower in male LL than in controls, but not in females. The increase in plasma insulin after oral glucose load was lower in LL than in controls, both in males and females at 4 and 16 months, and only in males at 10 months, whereas the change in plasma glucose remained constant between the groups. Results indicate that both the pancreatic [3-cell function and insulin sensitivity and adipose tissue metabolism are independently programmed as a consequence of under-nutrition during suckling, the effect being more manifest for males than for females.

Background/Aims: In order to determine whether the response to a sucrose-rich diet (SRD) during pregnancy in the rat varies depending on the strain, the responsiveness to a SRD (63 g sucrose/100 g) during pregnancy in Wistar and Sprague-Dawley rats was studied. Methods: One group of rats of each strain was fed the SRD, whereas another group received the same diet except that sucrose was replaced by an equal amount of cornstarch. Half of the rats were mated, and all animals were studied 20 days later. Results: Initial body weight did not differ among groups, but final body weight of pregnant Wistar rats was lower than in Sprague-Dawley, and this difference corresponded to a decrease in fetal body weight in the former. Feeding a SRD did not modify pregnancy outcome in either rat strain. Plasma triglycerides increased with a SRD, although this effect was milder in Wistar pregnant rats than in the other groups. Adipose tissue lipoprotein lipase activity was lower in pregnant than in virgin rats, but no differences were found as result of either diet or rat strain. Liver triglyceride concentration increased in virgin rats fed SRD, the effect being greater in Sprague-Dawley than in Wistar rats. Conclusion: Differences in the response to a SRD in pregnant and virgin rats do not depend on the strain of rats used.