Ask the Chatbot Games & Quizzes History & Society Science & Tech Biographies Animals & Nature Geography & Travel Arts & Culture ProCon Money Videos
protein hormone
References
Images
Diagram of a typical endocrine cell showing labeled internal structures, including the nucleus, endoplasmic reticulum, Golgi apparatus, cytoplasm, and secretory granules, with arrows illustrating the pathway of hormone synthesis and exocytosis.
Britannica AI Icon

protein hormone

biochemistry
Written by
The Information Architects of Encyclopaedia Britannica

The Information Architects maintain a master list of the topics included in the corpus of  Encyclopædia Britannica, and create and manage the relationships between them.
The Information Architects of Encyclopaedia Britannica
Last updated

Quick Summary

Diagram of a typical endocrine cell showing labeled internal structures, including the nucleus, endoplasmic reticulum, Golgi apparatus, cytoplasm, and secretory granules, with arrows illustrating the pathway of hormone synthesis and exocytosis.
Intracellular structure of a typical endocrine cell. The process of protein hormone synthesis begins when a hormone or an active metabolite stimulates a receptor in the cell membrane. This leads to the activation of specific molecules of DNA in the nucleus and the formation of a prohormone. The prohormone is transported through the endoplasmic reticulum, is packaged into secretory vesicles in the Golgi apparatus, and is ultimately secreted from the cell in its active, hormone form.

Protein hormones are a major class of hormones produced by endocrine glands. They are water-soluble and transported through the bloodstream. These hormones are synthesized from amino acids and initially exist as inactive prohormones, which are then split by enzymes into their active forms before release.1

Key aspects of protein hormones include:
* Synthesis: They are produced within cells, often directed by messenger RNA (mRNA) transcribed from DNA. The process involves the endoplasmic reticulum and Golgi apparatus before secretion.2
* Action: Protein hormones bind to specific receptors on the surface of target cells, initiating a cascade of chemical responses within the cell.1
* Examples: Hormones like insulin and glucagon, produced by the pancreas, are protein hormones. Thyroid hormones and calcitonin from the thyroid gland, as well as hormones from the pituitary gland such as growth hormone and luteinizing hormone, are also protein or peptide in nature.34

Summary created from Britannica articles using AI. AI can make mistakes, so verify using Britannica articles.
4 Britannica Sources
  1. human endocrine system - Traditional endocrinology
  2. human endocrine system - Hormone synthesis
  3. protein - Hormones of the thyroid gland
  4. protein - Hormones of the pancreas

Ask Britannica AI about this topic

Britannica doesn't have a full article on this topic, so we've curated a list of our relevant coverage.