Final answer:
Peptide hormones are stored in vesicles within the very cells that produce them and released in response to stimuli. They are water-soluble and require cell surface receptors to affect target cells because they cannot pass through cell membranes.
Step-by-step explanation:
Yes, peptide hormones can be stored in the endocrine cell that produces them. For instance, secreted peptides like insulin are stored within vesicles in the cells that synthesize them, awaiting release in response to specific stimuli, such as elevated blood glucose levels. These hormones are typically water-soluble and insoluble in lipids, preventing them from diffusing through the plasma membranes of cells. Therefore, they depend on cell surface receptors to exert their effect. The binding of peptide hormones to their respective receptors on target cells triggers a signaling pathway that results in the desired cellular response.
Receptors for peptide hormones are typically located in the plasma membrane, as most peptide and amino acid-derived hormones are lipid insoluble and are incapable of crossing the cell membrane to exert their effects intracellularly. Instead, the binding of these hormones to their receptors leads to the activation of second messengers inside the cell, which carry on the intended functions and maintain homeostasis within the body.