کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
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1972691 | 1060286 | 2012 | 6 صفحه PDF | دانلود رایگان |
Transepithelial transport mechanisms play a key role in regulating the absorption and secretion of calcium (Ca2 +) and inorganic phosphate (Pi) in the gastrointestinal tract. Although intestinal disorders with imbalances in macromineral homeostasis are frequently observed in horses, available data on intestinal Ca2 + and Pi transport are limited. The aim of the present study was to characterize the intestinal Ca2 + and Pi transport functionally by using the in vitro radioisotope tracer technique with Ussing chambers and to identify components involved in Ca2 + transport at both mRNA and protein level. Among the different intestinal segments, the duodenum showed significant and highest active Ca2 + absorption. The findings from RT-PCR and Western blot analysis suggest that the epithelial Ca2 + channel TRPV6, the cytosolic calcium binding protein calbindin-D9K and the plasma membrane calcium ATPase PMCA may be involved in active transcellular Ca2 + transport. Regarding the Pi transport, the results indicate significant active Pi secretion in the jejunum, but the contributing mechanisms remain unclear. A significant inhibiting effect of ouabain as an antagonist of the basolateral Na+/K+-ATPase on the serosal-to-mucosal Pi transport suggests a pivotal role of Na+ in jejunal Pi transport in the horse.
Journal: Comparative Biochemistry and Physiology Part A: Molecular & Integrative Physiology - Volume 161, Issue 2, February 2012, Pages 259–264