Inhibitory Action of Extracts of Mammalian Skin on Pigment Formation.

Abstract

Inhibition of melanin formation in vitro by aqueous extracts of human epidermis and of homogenates of rabbit skin is due to heat-stable, dialyzable, non-protein-like sulfhydryl compounds. A direct relationship exists between the -SH concn. and the inhibitory power of extracts of human epidermis. U.-v. irradiation causes an immediate decrease in the amount of water-extractable -SH compounds of the skin of colored rabbits. No such decrease could be observed in albino animals. These findings support the theory that pigment forming stimuli cause pigmentation by oxidizing or destroying the -SH compounds of the epidermis, whereupon the enzyme can freely act on the melanin precursor.