Final answer:
Peptide hormones are initially synthesized as larger precursors, which are then processed into their active forms. This synthesis involves the transcription of DNA to mRNA and the translation of mRNA to amino acid chains.
Step-by-step explanation:
Peptide hormones, which are chains of 50 or fewer amino acids, are initially synthesized as larger precursor proteins. These precursors undergo post-translational modifications, where additional amino acids can be added through the formation of peptide bonds, and eventually are cleaved to form the active hormone. The synthesis process starts with DNA being transcribed into mRNA.
The mRNA is then translated into an amino acid chain. In the beginning, peptide hormones are part of larger polypeptide chains that include a signal sequence that directs the protein to the endoplasmic reticulum and may contain other sequences that are necessary for the hormone to become fully functional.
Examples of peptide hormones include antidiuretic hormone (ADH), oxytocin, growth hormone (GH), and follicle-stimulating hormone (FSH), which highlight the wide variety of roles that peptide hormones play in pituitary gland functions and in the regulation of certain hormones.