The monocarboxylate transporters exist in the cattle endocrine pancreas.

Abstract

Extensive studies are published concerning the distribution of monocarboxylate transporters (MCTs) in various animal issues including ruminants; nonetheless, nothing is known about their cellular expression and localization in the ruminant pancreas. The present study was carried out to examine the expression and cellular localization of all the fourteen MCT isoforms in cattle pancreas. RT-PCR verified the existence of mRNA transcripts for eight MCT isoforms, namely, MCT1, MCT2, MCT3, MCT4, MCT5, MCT8, MCT13, and MCT14 in cattle pancreas. Western blotting analysis confirmed the protein expression of these eight MCTs in the cattle pancreatic tissue. Immunohistochemical study, within the whole pancreas, was conducted to localize the eight MCTs identified, and the results showed strong positive immunoreactive staining for MCT1, MCT2, MCT4, MCT5, MCT13, and MCT14 on nearly all the islet cells of Langerhans, while we could not detect immunopositive signals in the acinar cells with any of MCTs antibodies used. This study, for the first time, showed the cellular localization and expression of MCT1-MCT5, MCT8, MCT13, and MCT14 within the ruminant pancreas. The distribution and expression pattern of MCT1, MCT2, MCT4, and CD147 in the cattle pancreas are different from that previously published on monogastric pancreas. Our study suggested that MCT1, MCT2, MCT4, MCT5, MCT13, and MCT14 may participate in the regulation of the pancreatic endocrine secretions in ruminants.