How do peptide and steroid hormones function in target cell response?

Peptide and steroid hormones function differently in target cell response.

Peptide hormones are water-soluble and bind to receptors on the surface of target cells, triggering a secondary messenger system that leads to a cellular response. The secondary messenger system involves the activation of enzymes, such as adenylate cyclase and protein kinase, which ultimately lead to the activation of transcription factors and gene expression. This process is rapid and short-lived, with the hormone being quickly degraded.

Steroid hormones, on the other hand, are lipid-soluble and can pass through the cell membrane to bind to intracellular receptors. The hormone-receptor complex then enters the nucleus and binds to specific DNA sequences, regulating gene expression. This process is slower but longer-lasting, as steroid hormones are not quickly degraded.

The specific response of the target cell to a hormone depends on the type of hormone, the receptor it binds to, and the downstream signalling pathways activated. Peptide hormones are involved in a wide range of physiological processes, such as growth and metabolism, while steroid hormones are important in regulating reproductive and stress responses.

Overall, peptide and steroid hormones have distinct mechanisms of action in target cells, but both play important roles in maintaining homeostasis in the body.