GLOSSARY

A prohormone is an inactive or weakly active precursor molecule that must undergo enzymatic processing (cleavage or chemical modification) to become an active hormone; this step allows safe storage, precise control of secretion, and the production of several hormones from one precursor.

Peptide Examples

• Preproinsulin → proinsulin → insulin + C-peptide (cleaved in the Golgi).
• Pro-opiomelanocortin (POMC): precursor of ACTH, MSH, and beta-endorphin (processed differently in different tissues).
• Proglucagon: glucagon in the pancreas; GLP-1 and GLP-2 in the intestine.

Non-Peptide Examples