Malnutrition during lactation as a metabolic imprinting factor inducing the feeding pattern of offspring rats when adults. The role of insulin and leptin.

The aim of the present study was to determine the impact of malnutrition during early postnatal life and the feeding pattern of rat offspring when adults (2 months and 1 year old). In comparison with rats normally fed during lactation, we observed that adult offspring displayed a faster process of feeding reduction when a protein-free diet was offered. In addition, we studied the concentration of insulin and leptin in the lactating pups (10 days) and when these offspring became adult after the onset of a new feeding pattern induced by the protein-free diet. When the diet was changed at 60 days, the offspring malnourished during lactation displayed, after 3 days, a food intake reduction around 41.4 vs 14.2% of the control group. At 10 days of life, plasma leptin and insulin were higher in the malnourished pups when compared with normally fed rats (leptin: 4.6 +/- 0.8 vs 2.25 ng/ml; insulin: 0.73 +/- 0.12 vs 0.22 +/- 0.03 ng/ml) while at 60 days they showed reduction of both hormones when compared with the control group (leptin: 1.03 +/- 0.25 vs 1.43 +/- 0.5 ng/ml; insulin: 0.54 +/- 0.3 vs 0.61 +/- 0.4 ng/ml). Despite the different food intake reductions, the malnourished and control rats displayed a similar reduction of insulin and leptin after 3 days of protein-free diet (from 60 to 63 days). The data suggest that the high concentration of insulin and leptin found at 10 days in the malnourished pups may elicit a sustained long-term and unique feeding pattern.