Epinephrine-induced Pigment Aggregation in Goldfish Melanophoroma Cells: Apparent Involvement of an Unknown Second Messenger

Using a goldfish-derived melanized cell line, we attempted to determine the identity of the signal transduction system/second messenger for epinephrine-induced aggregation of melanosomes in a goldfish cell line. The results show that the second messenger is unknown. It is not 1) influx of extracellular calcium, 2) release of intracellular stored calcium via the phosphoinositide pathway, 3) cGMP, or 4) decrease of cAMP. These results suggest that there is an unknown second messenger for this activity of epinephrine.