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Reduced expression of the PTH/PTHrP receptor during development of the mammary gland influences the function of the nipple during lactation
Author(s) -
Kobayashi Tatsuya,
Kronenberg Henry M.,
Foley John
Publication year - 2005
Publication title -
developmental dynamics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.634
H-Index - 141
eISSN - 1097-0177
pISSN - 1058-8388
DOI - 10.1002/dvdy.20406
Subject(s) - mammary gland , lactation , medicine , endocrinology , biology , receptor , connective tissue , parathyroid hormone related protein , hormone , parathyroid hormone , pregnancy , calcium , cancer , breast cancer , genetics
Signaling by the parathyroid hormone/parathyroid hormone‐related protein receptor (Ppr) is necessary for mammary gland development beyond the early induction stage in mice. We used a series of murine models of reduced Ppr expression to determine how diminished receptor signaling influences mammary development. Reduction of Ppr expression to very low levels prevented mammary gland development. A less‐severe reduction in Ppr expression permitted progression of mammary gland development beyond the induction stage, but the nipples of these mice were dramatically smaller than those of controls, with altered epidermis and connective tissue. Mothers with reduced expression of Ppr could not successfully nurse pups; however, the lactating glands did produce milk but could not efficiently deliver it. This finding was associated with reduced levels of matrix metalloproteinase‐2 and an absence of pregnancy‐associated remodeling of connective tissue matrix in the nipple. Reduced smooth muscle appears to underlie the majority of nipple deficiencies in mice with lower levels of the Ppr expression. Developmental Dynamics 233:794–803, 2005. © 2005 Wiley‐Liss, Inc.