Expression and distribution of monocarboxylate transporter 1 (MCT1) in the gastrointestinal tract of calves.

In the present study the expression and distribution of monocarboxylate transporter 1 (MCT1) along the gastrointestinal tract (rumen, reticulum, omasum, abomasum, duodenum, jejunum, ileum, cecum and colon) of calves were investigated on both mRNA and protein levels. The expression of MCT1 protein and its distribution were determined by Western blotting and immunohistochemical staining, respectively by using antibody for MCT1. MCT1 protein was visualized as a 43-kDa band on immunoblots of the membrane proteins prepared from the various regions examined, and it was more highly expressed in forestomach and large intestine than in abomasum and small intestine. With the use of reverse transcriptase-polymerase chain reaction, mRNA encoding for MCT1 was demonstrated in the different tissues examined. The immunohistochemical study confirmed the Western blot findings and showed strong MCT1 immunopositive staining in the stratified squamous epithelia of the forestomach as well as the epithelial cells lining the digestive tract in the cecum, proximal colon, and distal colon. The results suggest that MCT1 may play a role in the transport of SCFA and their metabolites in the gastrointestinal tract of bovines.