Pigment-dispersing hormone 2 PDH2_CALSI MRSGVFVAVLVVVVFALLTQGQELHVPEREAVANLAARILKIVHAPHDAAAGVPHKRNSELINSLLGISALMNEAGRR 78 PDH2 PDH precursor-related peptide 2 Pigment-dispersing hormone 2 peptides The pigment-dispersing hormone causes the migration of the distal retinal pigment into the proximal end of the pigment chromatophore cells and thus decreases the amount of light entering the retinulas. May also function as a neurotransmitter and/or neuromodulator (By similarity).