Effect of nutritional rehabilitation of undernourished rats on serum insulin-like growth factor (IGF)-I and IGF-binding proteins

The aim of the present work was to study the effect of nutritional rehabili tation with different concentration of dietary protein (6, 18 or 50%) of pr eviously undernourished rats on serum Insulin-like growth factor-1 (IGF-1) and Insulin-like growth factor binding proteins levels (IGFBPs). Undernutri tion was induced by feeding rats with 0.5% casein diet for 5 weeks. Over th is period, growth, serum total proteins, ICF-1 levels and IGFBP-3/ IGFBP-2 ratio were significantly decreased compared to the group fed ad libitum 18% casein diet. Nutritional rehabilitation for 21 days with 6% casein diet di d not change any of these parameters. Nutritional rehabilitation with 18 or 50% casein diet for one day did not initiate the restoration of serum IGF- 1 levels and IGFBP-3/IGFBP-2 ratio. However, after 10 days with 18 or 50% c asein diets, there was an increase of 12 Fold in IGF-1 levels and 7 fold in the IGFBP-3/IGFBP-2 ratio. Finally, rehabilitation for 21 days with 18 or 50% casein diet produced an increase of 21 and 26 fold in IGF-1 levels, and 6.1 and 74.5 fold in the IGFBP-3/IGFBP-2 ratio respectively. These results suggest that nutritional rehabilitation with 18% casein and above were mor e effective than 6% casein diets to reestablish body weight. Serum IGF-1 an d IGFBP-3 concentrations were sensitive indicators of the evolution of the nutritional status of the rats depending of the protein concentration in th e diet in previously undernourished rats.