Three-dimensional organization of the rat parathyroid glands.

For the study of the three-dimensional organization of the rat parathyroids, some glands were freeze-fractured and others were mechanically dissociated. The main element of the parenchyma, the epithelial cords, corresponds to folds of an unistratified epithelium; the lateral cell surfaces are studded with microvilli and microplicae and the blood capillaries show irregularly sized fenestrations.