Premium
Lactational hormones increase expression of milk proteins but do not enhance uptake of copper by mammary epithelial cells
Author(s) -
Kim Stephen,
Kassissa Christine,
Kidane Theodros Z.,
Ackland Leigh,
Mercer Julian F.B.,
Linder Maria C.
Publication year - 2008
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.22.1_supplement.1192.1
Subject(s) - lactation , mammary gland , medicine , endocrinology , hormone , biology , chemistry , pregnancy , genetics , cancer , breast cancer
In lactation, a large portion of ionic copper entering the blood is diverted from the liver and kidney to the mammary gland and rapidly enters the milk. To determine whether this increased uptake of copper by the mammary gland might be due to the increased expression of specific copper transporters, we examined the response of the mammary epithelial cell to lactational hormones, using the human breast epithelial model (PMC42 cells) as well as cultured mouse mammary explants. Although the hormones induced increased expression of the milk protein, casein (as determined by Western blotting), uptake of 64 Cu delivered on alpha‐2‐macroglobulin, albumin, or the di‐histidine complex was not enhanced. Manipulation of the Matrigel concentration to grow the PMC42 cells as organoids rather than monolayers also made not difference to rates of copper uptake. Expression of CTR1 was not affected by hormone treatment. Our findings suggest that the increased number and volume of the epithelial cells occurring in lactation, rather than changes in uptake capacity per cell, account for the increased flow of copper into the mammary gland during the suckling period. Indeed, we found that uptake of tracer 64 Cu by mouse mammary gland increased in proportion to its weight already in gestation. Supported by PHS Grant No. RO1 HD 46949.