BETA-LACTOGLOBULIN SUPPRESSES MELANOGENESIS IN CULTURED HUMAN MELANOCYTES

The effects of whey proteins from bovine milk on melanogenesis in cult ured human melanocytes were examined. Among the major protein componen ts of milk whey including beta-lactoglobulin (BLG), alpha-lactalbumin, serum albumin, and IgG, only BLG exhibited the depigmenting effect at a concentration of 1 mg/ml. Also, BLG suppressed the activity of tyro sinase in these cells. Retinol, to which BLG is known io bind, slightl y increased the pigmentation of the cells at concentrations in the ran ge of 1-100 nM, and retinoic acid, a metabolite of retinol, exhibited a strong pigmentation-promoting effect within the same concentration r ange, Treatment of the cells with 1 mg/ml BLG completely abrogated the pigmentation induced by these A vitamins. These results demonstrate a novel biological activity of BLG and suggest that this activity is de pendent on its ability to hind retinol.