Perinatal feedings adversely affect lipogenic activities but not glucose handling in adult rats

The long-term effects of early under- and overfeeding on glucose metabolism and fat cell Lipogenesis were studied. Newborn rats were reared in Litter sizes of four, 10, and 16 pups. The amount of milk intake per pup varied in versely with litter sizes. A subgroup of pups from each group was studied a t age 20 d, whereas another subgroup was weaned to an ad libitum feeding of standard rat chow and studied at 12 wk of age. There were no differences a mong groups in food intake on the basis of per gram body weight. Overfeedin g during suckling resulted in fatter rats at weaning and in the adults. The higher fat contents in the adipose tissues and carcasses were associated w ith higher fatty acid synthase and lipogenic activities in the adipose tiss ues at weaning and 12 wk of age. Differences in plasma insulin and glucose levels among groups were observed only in the 20-d-old rats: basal insulin and glucose levels and 30-min postglucose insulin levels were highest in th e overnourished and lowest in the undernourished rats. However, by 12 wk of age, there were no significant differences among groups in their basal ins ulin and glucose levels and after an oral dose of glucose. Our results sugg est that overfeeding or underfeeding during the suckling period affects the glucose-insulin axis only temporarily and not permanently, but early overf eeding permanently enhances fatty acid synthase and lipogenic activities in adipose tissues, resulting in fatter adult rats.