Embryonic Epithelial Development is Modulated by Extracellular Calcium

This study investigated the effects of calcium on epithelial differentiation in organ-cultured embryonic chick duodenum. Alteration of calcium ion concentration of culture medium above or below the physiological Ca2+ concentration of embryonic chick serum strongly influenced gastrointestinal development. Culture of 16- or 18-day embryonic intestine in high Ca2+ resulted in elevated activity of alkaline phosphatase, a brush border digestive enzyme, and an increase in goblet cell number within the epithelium. Conversely, low Ca2+ reduced both indices of functional differentiation. Lead acetate, a disruptor of Ca2+ homeostasis, was as effective as low Ca2+ in impeding epithelial differentiation. The voltage sensitive Ca2+-channel (VSCC) antagonists verapamil and nifedipine were used to selectively block Ca2+ influx into the cultured tissue. Both verapamil, a non-specific channel blocker, and nifedipine, which is highly selective for L-type VSCCs, significantly inhibited differentiation, but nifedipine gave more consistent results. Imaging of calcium within the epithelium of cultures was performed by confocal scanning laser microscopy, using the fluorescent calcium probe indo-1. Quantification of Ca2+ within enterocytes revealed that both verapamil and nifedipine reduced intracellular Ca2+ concentration. Together, these results indicate that extracellular Ca2+ influences epithelial differentiation by modulating intracellular Ca2+-dependent signaling pathways, possibly mediated by VSCCs.

Author dc:creator

• Mack, Cina Marie

Advisors dc:contributor.advisor

• Dr. Betty L. Black, Committee Co-Chair
• Dr. Russell Borski, Committee Co-Chair
• Dr. Robert Argenzio, Committee Member
• Dr. Herbert Underwood, Committee Member

• calcium
• regulation
• extracellular
• embryo
• epithelium

Statement dc:rights

• I hereby certify that, if appropriate, I have obtained and attached hereto a written permission statement from the owner(s) of each third party copyrighted matter to be included in my thesis, dissertation, or project report, allowing distribution as specified below. I certify that the version I submitted is the same as that approved by my advisory committee. I hereby grant to NC State University or its agents the non-exclusive license to archive and make accessible, under the conditions specified below, my thesis, dissertation, or project report in whole or in part in all forms of media, now or hereafter known. I retain all other ownership rights to the copyright of the thesis, dissertation or project report. I also retain the right to use in future works (such as articles or books) all or part of this thesis, dissertation, or project report.

Dc Identifier Other

etd-08162002-133025

OAI record oai:identifier

https://repository.lib.ncsu.edu/server/oai/request?verb=GetRecord&metadataPrefix=dim&identifier=oai%3Arepository.lib.ncsu.edu%3A1840.16%2F3316