What signifies the synthesis method of peptide hormones?

The synthesis method of peptide hormones is characterized by being stored in lipid vesicles until they are released. Peptide hormones are synthesized as precursors in the endoplasmic reticulum and then processed in the Golgi apparatus, where they are packaged into secretory vesicles. These vesicles contain the active forms of the hormones, which remain stored until the appropriate signal triggers their release into the bloodstream.

This mechanism allows for a rapid response to physiological needs, as the hormones do not need to be synthesized de novo every time they are required. Instead, the storage in vesicles ensures that they are readily available for secretion in response to stimuli such as changes in ion concentrations, hormonal signals, or other regulatory factors. This differs significantly from lipid-soluble hormones, which can diffuse freely through cell membranes and are not stored in vesicles.

The other options do not accurately reflect the synthesis and release processes of peptide hormones: peptide hormones are not produced on demand in the same sense as steroids; they do not freely diffuse in the cytoplasm as their action is mediated through binding to specific receptors after release; and they do not wait for direct binding stimuli before synthesis, since they are already preformed and stored for immediate use.