The basal lamina of the postnatal mammary epithelium contains glycosaminoglycans in a precise ultrastructural organization

• Published in: Developmental biology Vol. 74; no. 1; pp. 118 - 135
• Main Authors: Gordon, Joseph R., Bernfield, Merton R.
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 1980
• Subjects: Animals; Epithelium - metabolism; Epithelium - ultrastructure; Female; Glycosaminoglycans - analysis; Lactation; Mammary Glands, Animal - metabolism; Mammary Glands, Animal - ultrastructure; Mice; Mice, Inbred C3H; Pregnancy
• ISSN: 0012-1606; 1095-564X
• DOI: 10.1016/0012-1606(80)90056-1

The mammary epithelium was investigated to determine whether glycosaminoglycans (GAG) are components of the basal lamina of epithelia undergoing postnatal morphogenesis. Isolated epithelial tissues from midpregnant mice produce substantial amounts of GAG, consisting predominantly of hyaluronic acid and heparan sulfate. The basal surfaces of mammary epithelia at various postnatal developmental stages show GAG, as demonstrated by histochemistry and by autoradiography coupled with enzyme susceptibility. Electron microscopy using ruthenium red staining reveals polyanionic components, presumably GAG, within the epithelial basal lamina. Detailed ultrastructural analyses of tannic acid-treated and ruthenium red-stained material demonstrate that the lamina contains a two-dimensional symmetrical array of tetragonally ordered components colsely associated with the basal plasma membrane. This array is similar to that found in the hyaluronate-containing lamina of embryonic epithelia. A structurally ordered complex of GAG-containing macromolecules may characterize the basal lamina of all epithelia which undergo morphogenetic changes in cell shape.