POMC is synthesized in corticotrophs of the anterior pituitary from the 267-amino-acid-long polypeptide precursor pre-pro-opiomelanocortin (pre-POMC), by the removal of a 26-amino-acid-long signal peptide sequence during translation.

Each of these peptides is packaged in large dense-core vesicles that are released from the cells by exocytosis in response to appropriate stimulation:[citation needed] The POMC gene is located on chromosome 2p23.3.

This gene encodes a 285-amino acid polypeptide hormone precursor that undergoes extensive, tissue-specific, post-translational processing via cleavage by subtilisin-like enzymes known as prohormone convertases.

However, there are at least 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.

[citation needed] The processing of POMC involves glycosylations, acetylations, and extensive proteolytic cleavage at sites shown to contain regions of basic protein sequences.

In some tissues, including the hypothalamus, placenta, and epithelium, all cleavage sites may be used, giving rise to peptides with roles in pain and energy homeostasis, melanocyte stimulation, and immune modulation.

During spring in this species, when there is more than 13 hours of light per day, iodothyronine deiodinase 2 (DIO2) promotes the conversion of the prohormone thyroxine (T4) to the active hormone triiodothyronine (T3) through the removal of an iodine atom on the outer ring.

[9] Influences of photoperiods on relevant similar biological endocrine changes that demonstrate modifications of thyroid hormone regulation in humans have yet to be adequately documented.

The production of β-MSH occurs in humans but not in mice or rats due to the absence of the enzymatic processing site in the rodent POMC.