One precursor, many hormones
Pro-opiomelanocortin (POMC) is a large precursor protein that is cut by enzymes called prohormone convertases into several smaller, active peptides. Depending on the tissue and which enzymes are present, POMC yields adrenocorticotropic hormone (ACTH), the melanocyte-stimulating hormones (such as alpha-MSH), beta-endorphin, and other fragments.
This is a clear example of post-translational processing: the same gene product gives rise to different signaling molecules because cells process it differently. The pituitary, for instance, favors ACTH production, while other sites generate more MSH peptides.
What the derivatives do
ACTH travels to the adrenal glands and stimulates cortisol release, making POMC central to the stress axis. Alpha-MSH acts on melanocortin receptors involved in skin pigmentation and, in the hypothalamus, in appetite suppression. Beta-endorphin is an endogenous opioid peptide linked to pain modulation.
Because so many signals share one origin, conditions affecting POMC processing can have wide-ranging effects, which is why POMC is studied in pigmentation, stress, and appetite regulation. This is general educational information and not medical advice.