Peptide hormone


Peptide hormones are hormones composed of peptide molecules. These hormones influence the endocrine system of animals, including humans. Most hormones are classified as either amino-acid-based hormones or steroid hormones. Amino-acid-based hormones are water-soluble and act on target cells via second messenger systems, whereas steroid hormones, being lipid-soluble, diffuse through plasma membranes to interact directly with intracellular receptors in the cell nucleus.
Like all peptides, peptide hormones are synthesized in cells from amino acids based on mRNA transcripts, which are derived from DNA templates inside the cell nucleus. The initial precursors, known as preprohormones, undergo processing in the endoplasmic reticulum. This includes the removal of the N-terminal signal peptide and, in some cases, glycosylation, yielding prohormones. These prohormones are then packaged into secretory vesicles, which are stored and released via exocytosis in response to specific stimuli, such as an increase in intracellular Ca2+ and cAMP levels.
Prohormones often contain extra amino acid sequences necessary for proper folding but not for hormonal activity. Specific endopeptidases cleave the prohormone before secretion, producing the mature, biologically active hormone. Once in the bloodstream, peptide hormones travel throughout the body and bind to specific receptors on target cell membranes.
Some neurotransmitters are secreted and released in a manner similar to peptide hormones, and certain "neuropeptides" function as both neurotransmitters in the nervous system and hormones in the bloodstream.
When a peptide hormone binds to its receptor on the cell surface, it activates a second messenger within the cytoplasm, triggering signal transduction pathways that lead to specific cellular responses.
Certain peptides, such as angiotensin II, basic fibroblast growth factor-2, and parathyroid hormone-related protein, can also interact with intracellular receptors in the cytoplasm or nucleus through an intracrine mechanism.

Partial list of peptide hormones in humans

  1. Adrenocorticotropic hormone
  2. Adropin
  3. Amylin
  4. Angiotensin
  5. Atrial natriuretic peptide
  6. Calcitonin
  7. Cholecystokinin
  8. Gastrin
  9. Ghrelin
  10. Glucagon
  11. Glucose-dependent insulinotropic polypeptide
  12. Glucagon-like peptide-1
  13. Growth hormone
  14. Follicle-stimulating hormone
  15. Human chorionic gonadotropin
  16. Insulin
  17. Leptin
  18. Luteinizing hormone
  19. Melanocyte-stimulating hormone
  20. Orexin/Hypocretin
  21. Oxytocin
  22. Parathyroid hormone
  23. Prolactin
  24. Renin
  25. Somatostatin
  26. Thyroid-stimulating hormone
  27. Thyrotropin-releasing hormone
  28. Vasopressin, also called arginine vasopressin or anti-diuretic hormone
  29. Vasoactive intestinal peptide
  30. Somatotropin
  31. Gonadotropin Releasing Hormone 1
  32. Gonadotropin Releasing Hormone 2
  33. Growth Hormone Releasing Hormone
  34. Parathyroid Hormone Like Hormone
  35. Corticotropin Releasing Hormone
  36. Anti-Müllerian Hormone
  37. Chorionic Somatomammotropin Hormone 1
  38. Chorionic Somatomammotropin Hormone 2
  39. Pro-Melanin Concentrating Hormone
  40. Resistin