The Incretin/GLP-1 Revolution in Obesity Treatment

Vocabulary flashcards covering the discovery, physiology, clinical data, emerging applications, and limitations of incretin and GLP-1 anti-obesity therapies based on lecture notes.

Incretin

An intestinal hormone that stimulates the pancreas to increase insulin secretion in response to oral nutrient intake.

The Incretin Effect

The physiological phenomenon where oral glucose administration produces a substantially greater insulin secretion response than intravenous glucose, accounting for approximately $\frac{2}{3}$ of total post-meal insulin release.

GLP-1 (Glucagon-Like Peptide-1)

An intestinal incretin hormone released into the blood in response to food that stimulates insulin secretion, promotes glucose storage, decreases hepatic glucose release, and signals satiety.

Radioimmunoassay

An immunological measurement technique developed by Berson and Yalow that enabled the precise measurement of insulin concentrations in blood, allowing the incretin effect to be experimentally demonstrated.

extendin-4

A protein discovered in Gila monster saliva that mimics GLP-1 actions by raising blood insulin and lowering blood glucose, but lasts for hours in circulation because it is resistant to human enzymatic degradation.

Exenatide

The first GLP-1 receptor agonist drug approved by the FDA for the treatment of diabetes, which was developed based on extendin-4 isolated from Gila monster saliva.

The Intestinal Brake

A satiety and nutrient storage program activated when food reaches the distal small intestine (ileum), triggering intestinal hormones that increase insulin-mediated nutrient storage and signal satiety to reduce food intake.

Retatrutide

A triple GLP-1/GCG/GIP receptor agonist drug that demonstrated a $-24.2\%$ mean body weight loss at a $12\,mg$ weekly dose over $48\,weeks$ in clinical trials.

Tirzepatide

A dual GLP-1/GIP receptor agonist (brand names Mounjaro and Zepbound) approved for diabetes and weight loss that significantly reduces body weight and decreases the Apnea-Hypopnea Index in sleep apnea trials.

Semaglutide

A GLP-1 receptor agonist (brand names Wegovy and Ozempic) approved for diabetes and weight loss that reduces major cardiovascular events, decreases kidney disease progression, and lowers risks of cognitive deficits and nicotine misuse.

Anhedonia

A general reduction in the ability to experience pleasure or reward, identified as a potential effect of GLP-1 drugs mediated by brain GLP-1 receptors involved in appetite and reward systems.

Real-World GLP-1 Discontinuation Rate

The real-world clinical pattern where approximately $50\%$ to $70\%$ of patients stop taking GLP-1 medications within the first year ($30\%$ to $50\%$ persistence rate), in contrast to trial dropout rates of under $5\%$ to $10\%$.

Lean Tissue Loss

The proportion of body weight lost as muscle tissue during weight loss therapy, which can reach $35\%$ to $40\%$ in individuals starting with lower initial percentage body fat and is higher in males and older adults.

Global Overweight and Obesity Projection (2020-2035)

Epidemiological data projecting that the proportion of the global population aged over $5\,years$ with overweight or obesity will increase from $38\%$ ($2,603\,million$) in $2020$ to $51\%$ ($4,005\,million$) by $2035$.