Referenced in: none

Automatically associated channels: Kir6.2

Title: Calcium homeostasis and vitamin D metabolism and expression in strongly calcifying laying birds.

Authors: Arie Bar

Journal, date & volume: Comp. Biochem. Physiol., Part A Mol. Integr. Physiol., 2008 Dec , 151, 477-90

PubMed link: http://www.ncbi.nlm.nih.gov/pubmed/18682298

Abstract
Egg laying and shell calcification impose severe extra demands on ionic calcium (Ca2+) homeostasis; especially in birds characterized by their long clutches (series of eggs laid sequentially before a "pause day"). These demands induce vitamin D metabolism and expression. The metabolism of vitamin D is also altered indirectly, by other processes associated with increased demands for calcium, such as growth, bone formation and egg production. A series of intestinal, renal or bone proteins are consequently expressed in the target organs via mechanisms involving a vitamin D receptor. Some of these proteins (carbonic anhydrase, calbindin and calcium-ATPase) are also found in the uterus (eggshell gland) or are believed to be involved in calcium transport in the intestine or kidney (calcium channels). The present review deals with vitamin D metabolism and the expression of the above-mentioned proteins in birds, with special attention to the strongly calcifying laying bird.