Pinealocytes are the main cells of the pineal gland. They produce and secrete melatonin. Pinealocytes have an organelle called
synaptic ribbon, this is considered to be a specific marker for pinealocytes. Some of the enzymes of the pinealocytes include 5-HT N-acetyl transferase and 5-hydroxyindole-O-methyltransferase which are used to convert serotonin to melatonin.