What are the pituitary hormones that stimulate the production of melanin in the body?

Melanocytes. Melanin is produced by melanocytes located in your hair, eyes, and skin. It is the pigment that is responsible for skin color. They are not produced by the pituitary. You might be thinking of melatonin which is produced by the pineal gland and is responsible for the modulation of wake/sleep patterns and seasonal functions. I hope this useful. Take care and well wishes.