Produced in adenohypophysis.
Pars Intermedia may secrete two forms. Pars Intermedia virtually nonfunctional in adults excepts during (1) fetal development, (2) in very yound children, (3) in pregnant women, and (4) in course of some diseases.
Stimulates melanocytes of skin, increasing production of melanin (brown, black, yellow-brown pigment).
Inhibited by Dopamine.
Important in control of skin pigmentation in fishes, amphibians, reptiles, and many mammals other than primates.
In humans, produced locally, within sun-exposed skin.