Ep1: Hormones and Hormone-related Diseases
Hi all, as part of the Hormones and Hormone-related Diseases series, each week I’ll be delving into a key hormone/hormone-deficient disease and today’s hormone is…INSULIN!!
Insulin: Structure, Function, and History
❓What is Insulin?
Insulin is a hormone secreted by beta cells, which are found in clusters called the islets of Langerhans in the pancreas. It helps regulate blood glucose levels by promoting glucose uptake into cells.
⚕️How does it work?
Insulin is complementary to receptors on cell membranes (including those in the liver and muscles, not the pancreas itself). When insulin binds to its receptor, it triggers glucose channels to open, allowing glucose to enter cells and be used or stored (in respiration) — helping lower blood sugar levels.
💊 Insulin and how it relates to Diabetes:
In Type 1 Diabetes, the body cannot produce insulin. People with this condition often need insulin injections.
The first successful treatment was in 1922 by the University of Toronto, using insulin extracted from cattle pancreases to save a 14-year-old boy who was previously dying from T1 diabetes. He was saved. Dr. Frederick Banting and Charles Best discovered the hormone.
💉Common Injection Sites:
· Front of the thighs
· Around the belly button (where there’s more fat for comfortable absorption)
🧪Molecular Structure:
· Made of 51 amino acids
· Two chains: A-chain and B-chain, connected by disulfide bridges
· Originally produced as a 110-amino acid chain and later processed
· Contains carboxyl groups, amine groups, peptide bonds, and disulfide bridges (especially between cysteine residues) — these maintain its tertiary structure
🏛️Quaternary Structure:In the pancreas, insulin forms dimers and then hexamers for storage. When released, they break down into monomers, the active form that travels in the bloodstream.