Effects of alpha-melanocyte-stimulating hormone on calcium concentration in SZ95 sebocytes

Melanocortins have been implicated in human sebum secretion for a long time. However, the signalling pathways of alpha-melanocyte-stimulating hormone (alpha-MSH) in human sebocytes expressing melanocortin receptors (MC-Rs) are still poorly understood. Because calcium ions play a central role in MC-R signalling, we investigated whether alpha-MSH affects calcium signalling in the immortalized human sebocyte cell line SZ95. In addition, we investigated the impact of alpha-MSH on MC-1R expression and lipid synthesis in these cells. alpha-MSH increased intracellular calcium levels. alpha-MSH-mediated calcium mobilization originated from intracellular calcium stores and was mediated by inositol triphosphate. Moreover, alpha-MSH increased MC-1R immunoreactivity and lipid synthesis in SZ95 sebocytes in the presence of testosterone. Our data demonstrate that alpha-MSH in human sebocytes controls a key cellular signalling pathway, the calcium ion response, which may coordinate MC-1R-mediated sebum secretion.