Ultrastructural study of hydrocortisone action in cultured human epidermis.

Adult human skin was maintained in organ culture in a chemically defined medium without serum for up to 10 days. Under these conditions cultured epidermis revealed ultrastructural changes suggesting alterations in keratinization. Half of the newly formed stratum corneum became parakeratotic. The number and size of keratohyalin granules were reduced, and only few keratinosomes were present after the 5th day of culture. The effect of hydrocortisone at final concentrations of 10(-5)-10(-9) mol/l was studied by applying stereological techniques for electron microscopic morphometry on systematically sampled tissues. The volume densities of tissue components and cell organelles were assessed at three different strata of epidermis on the 5th day of culture. Changes of keratinization due to the culture conditions were partly reversed by the hormone, i.e. hydrocortisone increased the volume densities of keratohyalin granules, keratinosomes and tonofilaments. Minute effects due to hormonal action were seen on tissue components or the volume densities of other cellular organelles.