Lipogenesis in human skin.

In recent years there has been increasing appreciation of the metabolic activities that occur in the skin. The concept that the skin may manufacture the complex substances necessary to perform its function is gaining increasing support. In the category of lipids it seems possible that the skin itself synthesizes from other substances the fats necessary for the epidermal "barrier," the protective and emollient surface film and perhaps the precursors of Vitamin D. Srere, Chaikoff and others (1) reported that in rats the skin was one of the most active extrahepatie sites of sterol synthesis. Nieolaides, Reiss and Langdon (2) incubated slices of a piece of human scalp obtained at operation with C14 acetate and after careful separation of the lipid constituents demonstrated incorporation of the C' into sterols, fatty acids and also in sizable amounts into squalene (a precursor of the sterols which does not normally accumulate in other tissues). Later Nicolaides and Rothman (3) used an amputated limb as a source of human skin and incubated epidermis and dermis separately with C'4 acetate. They concluded that the epidermis was the main site of sterol synthesis in the human skin and that the sebaeeous glands synthesized and accumulated squalene. The present studies were undertaken to attempt to confirm and extend these observations and to apply, if possible, these methods of study to small (punch-biopsy size) pieces of skin.