According to new research from the Monell Center and the Mount Sinai School of Medicine, certain common herbicides and lipid-lowering fibrate drugs act in humans to block T1R3, a nutrient-sensing taste receptor also present in intestine and pancreas.
Commonly used in agriculture and medicine, these chemical compounds were not previously known to act on the T1R3 receptor.
The T1R3 receptor is a critical component of both the sweet taste receptor and the umami (amino acid) taste receptor. First identified on the tongue, emerging evidence indicates that T1R3 and related taste receptors also are located on hormone-producing cells in the intestine and pancreas.
These internal taste receptors detect nutrients in the gut and trigger the release of hormones involved in the regulation of glucose homeostasis and energy metabolism.
“Compounds that either activate or block T1R3 receptors could have significant metabolic effects, potentially influencing diseases such as obesity, type II diabetes and metabolic syndrome,” noted Monell geneticist and study leader Bedrich Mosinger, M.D., Ph.D.
In the study, published online in the Journal of Medicinal Chemistry, researchers tested the ability of two classes of chemical compounds to block the T1R3 receptor. The compounds – fibrates and phenoxy-herbicides – were selected based on their strong structural similarity to lactisole, a sweet taste inhibitor that exerts its taste effects by blocking T1R3.
Fibrates are a class of drugs frequently used to treat lipid disorders such as high blood cholesterol and triglycerides. Phenoxy-herbicides are used in agriculture to control broad-leaf weeds; the best known, 2,4-D, is one of the most extensively used herbicides worldwide.
Using an in vitro preparation, the researchers found that both classes of compounds potently blocked activation of the human sweet taste receptor, acting at micromolar concentrations to inhibit binding of sugars to the T1R3 component of the receptor.
Additional testing revealed that the inhibitory effect of both fibrates and phenoxy-herbicides on the T1R3 receptor is specific to humans. That is, the ability of these compounds to block the receptor did not generalize across species to the rodent form of the receptor. …
This is another important reminder that testing on mice and rats does not always show the real damage chemicals can do to humans. Perhaps people with type II diabetes can be helped by avoiding common herbicides and fibrates?