Peptide hormones

Definition

Peptide hormones are short chains of amino acids that function as signaling molecules in the body. They regulate a variety of physiological processes, including metabolism and calcium homeostasis.

5 Must Know Facts For Your Next Test

1. Peptide hormones such as calcitonin and parathyroid hormone (PTH) play crucial roles in calcium regulation.
2. Calcitonin lowers blood calcium levels by inhibiting osteoclast activity and increasing renal calcium excretion.
3. Parathyroid hormone (PTH) increases blood calcium levels by stimulating osteoclasts, enhancing intestinal absorption of calcium, and reducing renal excretion.
4. Peptide hormones generally have a short half-life and require frequent administration if used therapeutically.
5. Due to their protein structure, peptide hormones are typically administered via injection rather than orally.

Review Questions

• What is the primary role of calcitonin in calcium homeostasis?
• How does parathyroid hormone (PTH) affect blood calcium levels?
• Why are peptide hormones usually administered via injection?

Related terms

Calcitonin:

A peptide hormone produced by the thyroid gland that lowers blood calcium levels.

Parathyroid Hormone (PTH): A peptide hormone produced by the parathyroid glands that raises blood calcium levels.

Osteoclasts: Cells that break down bone tissue, releasing calcium into the bloodstream.