ACTH occurs in cells of the anterior pituitary and in neurons in brain. It regulates the corticosteroid production in the adrenal cortex. Beta endorphin and Met enkephalin are endogenous opiates. MSH (melanocyte stimulating hormone) increases the pigmentation of skin by increasing melanin production in melanocytes.There are eight potential cleavage sites within the polypeptide precursor and, depending on tissue type and the available convertases, processing may yield as many as ten biologically active peptides involved in diverse cellular functions. The encoded protein is synthesized mainly in corticotroph cells of the anterior pituitary where four cleavage sites are used; adrenocorticotrophin, essential for normal steroidogenesis and the maintenance of normal adrenal weight, and lipotropin beta are the major end products.
