Fig. 3. Prostate epithelial spheroids grown in Matrigel, KSFM plus 2% serum, 20-7 M dihydrotestosterone, 10 ng/ml estrogen, and stroma (sample C). A, phase image. Bar, 70 µm, the approximate diameter of one spheroid. B, TEM of whole spheroid. Bar, 10 µm. C, high magnification TEM of a whole cell within the spheroid. Secretory vesicles (sv) are all polarized toward the lumen, and microvilli (mv) are also visible on the luminal surface. Bar, 6 µm. D, high magnification TEM showing the luminal half of an epithelium (shown in C). The figure shows a large active golgi (g) and stacked rough endoplasmic reticulum. In addition, a tight junction (TJ) is visible at the luminal surface. Bar, 2 µm. E, a desmosomal-like junctional complex (D) present at a cell:cell interface on a luminal edge. Bar, 1 µm. F, basal edge of spheroid showing that no intact basal lamina was visible. Bar, 1 µm.