NEW YORK, July 21 — A class of medications originally designed for type 2 diabetes is drawing new attention for its potential to help with conditions that have long frustrated doctors and patients alike. Glucagon-like peptide-1 receptor agonists — GLP-1 agonists, for short — work by activating a receptor found on pancreatic beta cells and on neurons in the brain. They reduce blood sugar, curb appetite, and lower energy intake.
Some have already won approval for treating obesity. Now researchers are studying whether these same drugs might also help people with metabolic dysfunction–associated steatotic liver disease, polyendocrine metabolic ovarian syndrome, and diseases of the reward system, such as addictions, especially from ultra-processed foods.
How They Work in the Body
The mechanism behind GLP-1 agonists is both elegant and complex. In the pancreas, activating the GLP-1 receptor slows gastric emptying, inhibits the release of glucagon, and stimulates insulin production. That improves how the body handles glucose.
At the cellular level, binding to the receptor on beta cells raises intracellular cyclic AMP and activates protein kinase A, which triggers a calcium influx and prompts the exocytosis of insulin-containing vesicles. Beyond the pancreas, these drugs also ameliorate peripheral insulin resistance by upregulating phosphorylated IRS-1 and promoting the translocation of GLUT4 transporters to cell membranes in muscle and adipose tissue.
In the central nervous system, the story is different but equally important. GLP-1 receptor activation boosts activity of anorexigenic POMC and CART neurons in the hypothalamus while inhibiting orexigenic AgRP and NPY neurons. The drugs also counteract obesity-induced leptin resistance by downregulating inhibitory proteins SOCS3 and PTP1B, restoring the brain’s JAK/STAT signaling cascade.
For adipose tissue, GLP-1 agonists mitigate abnormal hypertrophic growth by downregulating lipogenic enzymes such as lipoprotein lipase and ANGPTL4. They also promote the “browning” of white adipose tissue into energy-burning brown adipose tissue.
This process, driven by activation of the AMPK and SIRT1 pathways, upregulates uncoupling protein 1, increasing thermogenesis and energy expenditure. Some of these metabolic effects are mediated through increased synthesis of fibroblast growth factor 21. That has spurred pharmaceutical companies to develop dual GLP-1/FGF21 receptor agonists, aiming to combine benefits.
Beyond Weight and Blood Sugar
Because of these wide-ranging actions, GLP-1 agonists are now under study for metabolic dysfunction–associated steatotic liver disease, a condition that affects millions. They are being investigated for polyendocrine metabolic ovarian syndrome, a hormonal disorder that can cause infertility and metabolic problems. And they are being studied for diseases of the reward system — addictions, especially to ultra-processed foods.
The native GLP-1 hormone that our own bodies produce has a short half-life. The enzyme dipeptidyl peptidase-4 (DPP-4) rapidly breaks it down.
That is why the pharmaceutical versions have been modified to extend their half-life, resulting in dosing schedules that range from daily to weekly or even less often. Another class of anti-diabetes drugs, DPP-4 inhibitors, work by a different approach — reducing the breakdown of the body’s own GLP-1. But they are generally considered less potent than GLP-1 agonists.
For patients, the choice of a drug often comes down to balancing effectiveness, side effects, and convenience. The science behind these medications is advancing quickly, with new dual-action compounds already in development.
As research continues, these drugs may offer new options for conditions that have long been difficult to treat. But each patient’s situation is unique, and decisions about their use should be made with a healthcare provider. Consult your doctor for medical advice.
