EXTRACTION OF OSMIUM ZINC IODIDE STAINING MATERIAL IN KERATINOSOMES.

Fixation or epidermis with osmium zinc iodide (OZI) for 24 hr at room temperature renders keratinosomes (lamellar granules of epidermis), the Golgi region, and mitochondria preferentially impregnated with heavy material while the remainder of the epidermal cell merely shows background staining. OZI fixation intensifies the heavy metal staining of the lamellae and of the envelope of keratinosomes. Extraction of epidermis with hexane prior to fixation with OZI abolishes the intensified impregnation of the lamellae and of the envelope of keratinosomes with the osmium zinc iodide stain. Because hexane theoretically extracts nonpolar lipids only and does not cause tissue disruption, it is suggested that the OZI-positive materials in keratinosomes are largely nonpolar lipids. [ABSTRACT FROM AUTHOR]