Abstract
Different classes of lipids human sebaceous glands were identified and localized using histochemical methods. Sebaceous glands contain phospholipids associated with the membranes of the mitochondria and the Golgi elements. The structure of the Golgi elements in sebaceous cells at different levels of differentiation shows a close relationship to what was related by the electron microscope. This supports the phenomenon that the Golgi region is the center of sebum formation. The sebaceous acinar cells do not contain any appreciable amount of sterols whereas sebum abounds in cholesterol esters which may come from keratinizing cells of sebaceous duct and philosebaceous canal and from disintegrating cells of the inner root sheath. Nile blue staining reveals that the newly formed sebum within the sebaceous cells is mainly composed of glycerides while old sebum contains both glycerides and free fatty acids. Surface lipids resemble sebum in composition, but they contain free cholesterol white sebum does not. This free cholesterol may originate from cholesterol esters through the action of nonspecific esterases.