Insecticides May Affect Body Clock, Raising Diabetes Risk

Chemicals in insecticides bind to receptors that regulate the biological clock, which suggests they could disrupt circadian rhythms and put those exposed at higher risk for diabetes, a new study has found.

The study from the University of Buffalo, published in the journal Chemical Research in Toxicology, used computer modeling to study millions of environmental agents, including household chemicals. The researchers were able to show for the first time that carbanates, widely used in insecticides, can affect melatonin signaling.

The research zeroed in on 2 well-known chemicals: carbonyl, the third most commonly used insecticide in the United States; and carbofuran, a toxic product that can no longer be used on crops grown as food. (However, the product has not been banned in Mexico.)

“We found that both insecticides are structurally similar to melatonin and that both showed affinity for the melatonin MT2 receptors, that can potentially affect glucose homeostatis and insulin secretion,” Marina Popevska-Goresvski, MS, a study co-author who now works for pharmaceutical manufacturer Boehringer Ingelheim, said in a press release. “That means exposure to them could put people at higher risk for diabetes and also affect sleeping patterns.

Irregular sleep has received increased attention as a trigger for greater insulin resistance, as research shows that people who work at night, and especially those with rotating shifts, are at higher risk for developing type 2 diabetes (T2D). Thus, the finding that a chemical reaction that mimics disrupted sleep in the body is consistent with recent work on the origins of disease development.

Right now, federal regulators do not examine how chemicals affect circadian rhythm, but the work being done at the University of Buffalo suggests this should be included in risk factors that get scrutinized. The university’s database includes 4 million chemicals that have some level of toxicity. The new study started with the database and put several hundred thousand chemicals in groups, based on their similarity, and identified those with chemical structures similar to melatonin. This allowed the researchers to confirm that carbanates can interact with melatonin receptors.

“By directly interacting with melatonin receptors in the brain and peripheral tissues, environmental chemicals, such as carbonyl, may disrupt key physiological processes leading to misaligned circadian rhythms, sleep patterns, and altered metabolic functions increasing the risk for chronic diseases, such as diabetes and metabolic disorders,” said Margarita Dubocovich, PhD, the study’s senior author and distinguished professor in the Department of Pharmacology and Toxicology.

Reference

Popovska-Gorevski M, Dubocovich ML, Rajnarayanan RV. Carbamate insecticides target human melatonin receptors. Chem Res Toxicol. 2017; doi: 10.1021/acs.chemrestox.6b00301.