Retinoids increase the incorporation of D-[3H]galactose into epidermal glycoproteins

All-trans retinoic acid increased the incorporation of D-[3H]galactose into particulate and soluble glycoproteins in the epidermis of cultured pig skin slices nearly two-fold. Increased incorporation of D-[3H]galactose was not blocked by tunicamycin. This effect was specific for D-[3H]galactose since the incorporation of D-[3H]glucosamine and L-[14C]leucine into epidermal glycoproteins was unaffected by all-trans retinoic acid. All-trans retinoic acid and 13-cis retinoic acid had quantitatively similar effects on D-[3H]galactose incorporation. All-trans retinyl acetate and an aromatic retinoic acid analogue ('Etretinate') were less effective. SDS polyacrylamide gel electrophoresis and fluorography showed increased incorporation of D-[3H]galactose into all epidermal glycoproteins in the presence of all-trans retinoic acid. There was no evidence for synthesis of new glycoproteins such as mucins.