Hyperpigmentation in Addison’s disease

Tyrosinase activity decreases after hypophysectomy, but can be restored by chronic administration of pituitary hormones like prolactin, MSH, and ACTH to a greater or lesser extent (131). Prolactin can promote in vivo melanin synthesis not only by stimulating tjn osinase activity, but also by increasing the supply of available substrate (131). However, it is still unknown which of the pituitary hormones is responsible for hyperpigmentation in Addison s disease in man. 

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