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Electron Microscopy of the Mouse Plantar Eccrine Sweat Glands

1970; Volume: 31; Issue: 3-4 Linguagem: Inglês

10.1679/aohc1950.31.455

0004-0681

Kazumasa Kurosumi, Utako KUROSUMI,

Erythrocyte Function and Pathophysiology

The eccrine sweat glands in the foot pads of adult mice of the C57BL strain fixed either with osmium tetroxide or with a mixture of glutaraldehyde and osmium tetroxide were observed with the electron microscope.The secretory portion of the eccrine gland consists of glandular cells and myoepithelial cells. After simple osmium fixation, the glandular cells show a rather uniform appearance, but the fixation with glutaraldehyde and osmium may reveal strong variations in electron density of the nucleus as well as the cytoplasm. Thus, the specimens after the latter fixation show glandular cells with three different grades of density, i.e., the dark, intermediate and clear cells.Microvilli of the dark cells are the shortest, those of the intermediate cell are intermediary and those of the clear cell are the longest, suggesting that the dark cell may be brought about through shrinkage of the cell. It is highly probable that the occurrence of dark and clear cells may be the result of fixation artefacts or of some pathological imbalance in water content from cell to cell.It is well known that the secretory vacuoles of the human and monkey eccrine sweat glands can be demonstrated as dark granules after fixation with glutaraldehyde and osmium. Those of the mouse gland, however, are always clear not only after simple osmium fixation but also after double or mixed fixation with glutaraldehyde and osmium. This implies that the substance in the secretory vacuoles of the mouse eccrine gland is chemically different to some extent from that of the human and monkey glands.The intercellular canaliculi which can be found in the human, monkey and cat eccrine glands and are lined exclusively with clear cells are not found in the mouse and rat glands. Therefore, it may be said that the rodent glands are primitive in structure.The agranular endoplasmic reticulum is first found in the animal eccrine glands in this study, and the agranular reticulum is intermingled with secretory vacuoles, though in the human gland the agranular reticulum appears exclusively in the basal clear cells while secretory vacuoles are prominent in the superficial dark cells. The fact that both structures occur in one and the same cell in the mouse gland may indicate that the mouse eccrine gland is undifferentiated.The above mentioned facts all suggest that the secretory cells of the rodent eccrine glands are essentially monotypical.The ultrastructure of the intradermal and intraepidermal sweat ducts was also described and the keratinization process of the duct cells was discussed.