Format

Send to

Choose Destination
J Mammary Gland Biol Neoplasia. 2005 Apr;10(2):119-28.

Calcium secretion into milk.

Author information

1
University of Colorado Health Sciences Center at Fitzsimmons, Aurora, 80010, USA.

Abstract

Ionized calcium ([Ca(2+)]) is present in milk at concentrations around 3 mM, a concentration that drives the formation of complexes with citrate, phosphate, and casein, thereby generating compounds that carry the major portion of calcium in milk. In humans and cows, where it has been studied, changes in milk calcium appear to be regulated by the amount of citrate and casein in milk rather than changes in [Ca(2+)]. Most or all of the calcium in milk is likely derived through exocytosis of secretory vesicles derived from the Golgi compartment where a calcium ATPase mediates transport from the cytoplasm. The identity of the transporters is not yet certain but gene expression for the plasma membrane calcium ATPase, PMCA2bw, and the secretory pathway calcium ATPase, SPCA, is highly upregulated during lactation. Currently nothing appears to be known about the mechanisms that mediate transport of calcium across the basolateral membrane of the alveolar cell.

PMID:
16025219
DOI:
10.1007/s10911-005-5395-z
[Indexed for MEDLINE]

Supplemental Content

Full text links

Icon for Springer
Loading ...
Support Center