introduction: effects of melatonin (mt) were comparatively examined on melanophores of isolated skin in adults and tadpole’s tailfin of a frog rana cyanophlyctis. mt is generally considered as a potent melanophores aggregating hormone besides regulating the sleep wake cycle in vertebrates. methods: melanophore size index (msi) was chosen as a recording parameter of the responses. concentration-...

Two melanotropic peptides, melanin concentration hormone (MCH) and alpha-melanocyte stimulating hormone (alpha-MSH), exert opposing actions on melanosome (melanin granule) movements within teleost pigment cells, melanocytes (melanophores). MCH stimulates melanosome aggregation to the cell center whereas alpha-MSH stimulates pigment organelle dispersion out into the dendritic processes of the me...