Figure 3.
Lifetime administration of 17β-estradiol alters the pattern of ERα expression in nontransgenic ovx nonparous aged females. A. Luminal ERα expression in morphologically normal ducts of a 2 year old ovariectomized (ovx) nontransgenic female (similar to 6 month old ovx, and ovx-E2 treated females). B. Basilar ERα expression in morphologically normal ducts of a 2 year old E2-treated ovx nontransgenic female. ERα-labeled cells (green) colocalize with cytokeratin 8 (K8; red) expression in ducts of ovx (C) and ovx/E2-treated (D) nontransgenic females. ERα labeled cells do not colocalize with cells expressing α-smooth muscle actin (α-SMA; red) in ducts of ovx (E) and ovx/ E2-treated (F) nontransgenic females. Representative micrographs. Original magnification: A, B, 400×; C-F, 600×. Prolonged 17β-estradiol administration reduces laminin 1α (G) and collagen IV α5 (H) transcripts with age. Nontransgenic FVB/N nonparous females were ovx post-pubertally, and thereafter were administered E2, as described in the Materials and Methods. RNA from whole mammary glands of 6 and 24 month old animals was examined for the myoepithelial ECM products by qRT-PCR as described in the Materials and methods. Each symbol denotes a single animal. Asterisks indicate the significant difference in laminin 1α mRNA between the 6 month and 24 month old animals (p=0.007; Student's t test).