Insulin‐like growth factor‐I (IGF‐I) mRNA in the small intestine of suckling and adult rats

Abstract
The presence and cellular localization of insulin‐like growth factor‐I (IGF‐I) mRNA in the small intestine of suckling and adult rats was studied. A sensitive reverse transcription (RT) competitive‐polymerase chain reaction (PCR) revealed IGF‐I gene expression in both age groups. Adult tissue contained 3‐fold higher levels of IGF‐I mRNA in comparison with sucklings. Using an in situ hybridization technique, IGF‐I transcripts were localized mainly in enterocytes and goblet cells in the intestinal crypts of adult rats. By using this technique, IGF‐I mRNA was not detected in jejunum of 12‐day‐old rats.