The distribution of endogenous epidermal growth factor after small bowel resection suggests increased intestinal utilization during adaptation

Background/Purpose: Although exogenous epidermal growth factor (EGF) amplifies adaptation after massive small bowel resection (SBR), the role for endogenous EGF is unclear. The authors sought to determine whether SBR was associated with changes in the levels of EGF in the serum, saliva, or urine and EGF receptor (EGF-R) signaling in the ileum. Methods: Male ICR mice underwent 50% proximal SBR or sham surgery bowel transection/reanastomosis). After 3 days, levels of EGF were measured by enzyme-linked immunosorbent assay (ELISA) in the serum, saliva, and urine. EGF-R activation was measured in isolated ileal enterocytes by probing an EGF-R immunoprecipitate with an antibody to phosphotyrosine. Results: When compared with sham, SBR resulted in no change in serum, increased salivary (2209 ± 266 nmol SBR v 1183 ± 119 nmol sham, P<.05) and decreased urinary (417 ± 58 nmol SBR v 940 ± 143 nmol sham; P< .05) EGF levels. EGF-R activation increased 2.5-fold after SBR. Conclusions: increased salivary and reduced urinary EGF linked with enhanced EGF-R activation suggests increased ileal utilization of EGF during adaptation. This observation, along with the known beneficial effects of exogenous EGF, infers a crucial role for endogenous EGF in the pathogenesis of intestinal adaptation after SBR.