Human melanocytes as a target tissue for hormones: In vitro studies with 1α-25, dihydroxyvitamin D3, α-melanocyte stimulating hormone, and beta-estradiol

Abstract Clinical evidence exists which suggests that normal pigment cell (melanocyte) function is subject to hormonal influences, but the nature of these interactions at a cellular level is poorly understood. We have investigated the effects of the vitamin D-derived secosteroid hormone 1α-25,dihydroxyvitamin D 3 (1,25(OH) 2 D 3 ), the pituitary-derived peptide alpha-melanocyte stimulating hormone (α-MSH), and the sex steroid beta-estradiol on melanocytes cultured from normal human foreskin. Human melanocytes specifically internalized 1,25(OH) 2 D 3 with high affinity (K d 0.5 – 0.8nM). Incubation with 1,25(OH) 2 D 3 (10 −9 M) for 48 h resulted in a 100% increase in 25-hydroxyvitamin D 3 -24-hydroxylase activity and a 50% increase in tyrosinase activity. There was no significant effect of 1,25(OH) 2 D 3 on intracellular cyclic adenosine monophosphate (cAMP). In contrast to 1,25(OH) 2 D 3 , α-MSH at a concentration of 5×10 −7 M caused a sevenfold increase in intracellular cAMP after 12 min but only a modest increase ( These results indicate that melanocytes from normal human foreskin in culture have the capacity to respond directly to several hormones. They also suggest that these cells form a useful model to study the effect of various hormones on pigment cell function.