Referenced in: none

Automatically associated channels: TRP , TRPV , TRPV6

Title: In vitro studies on intestinal calcium and phosphate transport in horses.

Authors: Anja Cehak, Mirja R Wilkens, Maria Guschlbauer, Nina Mrochen, Bernd Schröder, Karsten Feige, Gerhard Breves

Journal, date & volume: Comp. Biochem. Physiol., Part A Mol. Integr. Physiol., 2012 Feb , 161, 259-64

PubMed link: http://www.ncbi.nlm.nih.gov/pubmed/22119207

Abstract
Transepithelial transport mechanisms play a key role in regulating the absorption and secretion of calcium (Ca(2+)) and inorganic phosphate (P(i)) in the gastrointestinal tract. Although intestinal disorders with imbalances in macromineral homeostasis are frequently observed in horses, available data on intestinal Ca(2+) and P(i) transport are limited. The aim of the present study was to characterize the intestinal Ca(2+) and P(i) transport functionally by using the in vitro radioisotope tracer technique with Ussing chambers and to identify components involved in Ca(2+) transport at both mRNA and protein level. Among the different intestinal segments, the duodenum showed significant and highest active Ca(2+) absorption. The findings from RT-PCR and Western blot analysis suggest that the epithelial Ca(2+) channel TRPV6, the cytosolic calcium binding protein calbindin-D(9K) and the plasma membrane calcium ATPase PMCA may be involved in active transcellular Ca(2+) transport. Regarding the P(i) transport, the results indicate significant active P(i) 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 P(i) transport suggests a pivotal role of Na(+) in jejunal P(i) transport in the horse.