Cell contacts in the mouse mammary gland: I. Normal gland in postnatal development and the secretory cycle.

摘要: The nature and distribution of cell contacts have been examined in thin sections freeze-fracture replicas mammary gland samples from female C3H/Crgl mice at stages birth through pregnancy, lactation, postweaning involution. Epithelial cells major ducts all are linked their luminal borders by junctional complexes consisting tight junctions, variable intermediate occasional small gap one or more series desmosomes. Scattered desmosomes junctions link ductal epithelial myoepithelial combinations; hemidesmosomes attach to the basal lamina. Freeze-fracture confirm erratic reveal a loose, irregular network ridges comprising continuous tight-junctional belts. Alveoli develop early gestation initially resemble ducts. Later, as alveoli become actively secretory, they lose most whereas persist, becomes compact orderly, its undulating oriented predominantly parallel surface. It is suggested that these changes morphology, occurring secretory around parturition, may" be related greatly enhanced rate movement milk precursors products tbrough lactating epithelium, profound recurrent shape occur relation contraction, both.