Liver mRNA expression of IGF-I and IGFBPs in adult undernourished diabeticrats

To investigate the role played by factors other than GH, such as nutrients and insulin, on IGF-I secretion, adult male rats of 200 g.b.w, were food-re stricted for 7 days and then made diabetic by streptozotocin administration (UD). Different groups of UD rats were submitted to the following four day treatments: left untreated (UD), refed (UD+R), treated with insulin (UD+I) , or a combination of both refeeding and insulin (UD+R+I). Serum concentrat ion of IGF-I and liver mRNA expression of IGF-I, IGF-binding proteins and G H receptor were measured. Insulin treatment alone partially recovered liver IGF-I and IGFBPs mRNA expression, while refeeding alone had no effect. Onl y a combination of both insulin and refeeding recovered both parameters. Co ntrary to the results obtained with a longer period of recovery, these expe riments show that serum and mRNA expression of IGF-I and IGFBPs in adult un dernourished diabetic rats can be restored by insulin and nutrients adminis tration with no prior restoration of serum and pituitary GH to control valu es and no compensatory changes in GH receptor gene expression.