Total parenteral nutrition inhibits intestinal adaptive hyperplasia in young rats: reversal by feeding.

To determine whether the inhibition of intestinal adaptation by total parenteral nutrition (TPN) in young growing animals is reversible, 130 7-week-old rats with 70% resection of the midportion of the small bowel were given an amino acid and glucose TPN solution parenterally or orally or a chow diet for 10 days. After TPN administration, villous height, crypt depth, DNA and RNA content, RNA:DNA ratio, and sucrase activity were decreased. After returning to 4 weeks of chow feeding, rats given TPN achieved similar body weight and 15% greater intestinal length as compared with rats fed chow from the start, although their jejunal villous height, ileal crypt depth, and RNA:DNA were decreased. Therefore, the inhibition by TPN of intestinal adaptation after intestinal resection in young growing rats is largely reversible. Furthermore, oral feeding of a high-calorie, high-protein liquid diet before feeding of a normal diet appears to promote adaptation after intestinal resection in immature, growing rats.