Effects of Vitamin D on Calcium Absorption in Zebrafish Embryos (Danio rerio)
Date Issued
2009
Date
2009
Author(s)
Ting, Feng-Chun
Abstract
How animals maintain Ca2+ balance is an important issue because Ca2+ serves a variety of physiological roles. Ca2+ concentration usually fluctuates in freshwater environment. Facing Ca2+ changes, aquatic vertebrates must adjust Ca2+ absorption ability by regulating the expression of apical epithelial calcium channel (ECaC) on skin epithelial mitochondria-rich cells (MR-cells) to compensate intracellular Ca2+ level. During embryo stage, however, gills of freshwater teleosts are not well developed. At this stage, MR-cells on skin epithelium are main roles for ion regulation. To date, there are fewer studies on how endocrines regulate Ca2+absorption in teleosts, while a number of studies have shown that vitamin D affects the expression of ECaC in intestine and kidney in mammals. To see if this mechanism proposed in mammals has already existed in fish, which are more primitive than mammals in the aspect of evolution, is valuable for further research.he present study focused on effects of vitamin D on Ca2+ absorption in zebrafish. The mRNA expression of zebrafish vitamin D receptor-a (zVDRa) was detected as early as 3 hours postfertilization (hpf) and ubiquitously expressed in all tissues of zebrafish. Moreover, Ca2+ content, Ca2+ influx, and mRNA expression of zECaC were all increased, following vitamin D treatment. Finally, we found that Ca2+ content, Ca2+influx and the mRNA expression of zECaC decreased after zVDRa morpholino injection, but the expression of zebrafish Na+-Ca2+ exchanger 1b (zNCX1b) and zebrafish plasma membrane Ca2+-ATPase 2 (zPMCA2) were not affected. This study suggests that during the adaptation to fluctuating Ca2+ environment, vitamin D is one of the important factors regulating Ca2+ absorption in zebrafish embryos.
Subjects
Calcium
vitamin D
teleosts
ionoregulation
receptors
File(s)![Thumbnail Image]()
Loading...
Name
ntu-98-R95b45005-1.pdf
Size
23.32 KB
Format
Adobe PDF
Checksum
(MD5):778e3e345cbade9f50669aed18cee342