JOURNAL ARTICLE
RESEARCH SUPPORT, NON-U.S. GOV'T
Add like
Add dislike
Add to saved papers

Cloning, comparative sequence analysis and mRNA expression of calcium-transporting genes in horses.

Epithelial calcium transport occurs by paracellular and transcellular mechanisms. Transcellular transport in intestinal and renal epithelia involves several transport proteins, including transient receptor potential vanilloid member 5 (TRPV5), member 6 (TRPV6), calbindin D9k (CB9), calbindin D28k (CB28), sodium calcium exchanger 1 (NCX1), plasma membrane calcium ATPase 1 (PMCA1), and the vitamin D receptor (VDR). We are interested in the horse because of its unique calcium physiology (high blood calcium, high intestinal calcium absorption, high renal excretion of calcium, low vitamin D concentrations), and because horses often have dysregulated calcium balance with various diseases. We cloned the mRNA for equine TRPV5, TRPV6, CB9, CB28, NCX1, PMCA1, and VDR, performed comparative mRNA and protein sequence analysis, and quantified their mRNA expression in the kidney and gastrointestinal tract. Sequence homology for the mRNAs and proteins was high among mammals (>75%), with fish having the lowest homology (<75%). TRPV5, TRPV6, and CB9 expression was higher in the duodenum and proximal jejunum and followed a similar expression pattern. CB28 expression was greatest in the kidney. PMCA1 and NCX1 expression was similar throughout the intestine, but in the kidney PMCA1 expression was higher. Based on our findings, the proximal small intestine is the main site for transcellular calcium transport, with TRPV6 and CB9 serving as the main transport proteins. In the kidney, TRPV6, CB28, and PMCA1 are likely more important. The low VDR expression in the equine small intestine and kidney relative to the large intestine, together with the reported high intestinal absorption and renal excretion of calcium, and low vitamin D concentrations suggests that epithelial calcium transport in horses is not as dependent on vitamin D as in other species.

Full text links

We have located links that may give you full text access.
Can't access the paper?
Try logging in through your university/institutional subscription. For a smoother one-click institutional access experience, please use our mobile app.

For the best experience, use the Read mobile app

Mobile app image

Get seemless 1-tap access through your institution/university

For the best experience, use the Read mobile app

All material on this website is protected by copyright, Copyright © 1994-2024 by WebMD LLC.
This website also contains material copyrighted by 3rd parties.

By using this service, you agree to our terms of use and privacy policy.

Your Privacy Choices Toggle icon

You can now claim free CME credits for this literature searchClaim now

Get seemless 1-tap access through your institution/university

For the best experience, use the Read mobile app