Submitted to: Joint Meeting of the ADSA, AMSA, ASAS and PSA
Publication Type: Abstract Only
Publication Acceptance Date: March 2, 2010
Publication Date: July 10, 2010
Citation: Connor, E.E., Baldwin, R.L., Capuco, A.V., Clover, C.M., Ellis, S.E. 2010. Glucagon-like peptide 2 may mediate growth and development of the bovine gastrointestinal tract. Journal of Animal Science 88(2), E-Suppl:631. Technical Abstract: Glucagon-like peptide 2 (GLP-2), secreted by enteroendocrine cells, promotes growth, reduces apoptosis, and enhances blood flow, nutrient absorption, and barrier function in intestinal epithelium of monogastric species. Regulatory functions of GLP-2 in the ruminant gastrointestinal tract (GIT) are unknown. Our objectives were to characterize expression of GLP-2 pathway members throughout bovine GIT including proglucagon (GCG) mRNA, the parent peptide from which GLP-2 is derived through cleavage by prohormone convertase (PCK1), PCK1 mRNA, GLP-2 receptor (GLP2R) mRNA, and mRNA for dipeptidyl peptidase IV (DPP4), the enzyme that inactivates GLP-2. Gene expression was evaluated in rumen, reticulum, omasum, abomasum, duodenum, jejunum, ileum, cecum, and rectum collected at slaughter from prepubertal heifers, mature cows in early, mid, and late lactation, and non-lactating cows (n = 3/stage) by a multiplex gene expression profiling assay based on traditional RT-PCR that uses a universal priming strategy. Further, mRNA expression of 14 genes involved in nutrient transport, enzyme activity, blood flow, apoptosis, and proliferation were evaluated in the 9 GIT tissues for association with GCG and GLP2R mRNA. Results indicated that mRNA expression of GCG, PCK1, GLP2R, and DPP4 varies across the 9 GIT tissues (P < 0.001), with greatest expression in intestines, and generally non-detectable levels in forestomachs. Expression of DPP4 and GLP2R mRNA varied by developmental stage or lactational state (P < 0.05) in intestinal tissues. Expression of GCG or GLP2R mRNA was correlated with markers of proliferation, apoptosis, blood flow, enzyme activity, and urea transport, depending on tissue type, supporting involvement of GLP-2 in these processes in ruminants. Lastly, GLP2R protein was localized to cells lining the intestinal crypts by immunohistochemistry, consistent with distribution in monogastric species. Our findings support a functional role of GLP-2 in bovine GIT and its potential use to improve intestinal function and nutrient absorption in ruminants.