Researchers say two synthetic chemicals commonly found in insecticides and garden products called carbofuran and carbaryl bind to the receptors that govern our biological clocks. Exposure to these chemicals interferes with melatonin receptors, they say, creating a higher risk for metabolic diseases such as diabetes.
Disruptions in human circadian rhythms are known to put people at higher risk for diabetes and other metabolic diseases but the mechanism involved is not well-understood.
“This is the first report demonstrating how environmental chemicals found in household products interact with human melatonin receptors,” said Margarita L. Dubocovich, PhD, senior author on the paper and SUNY Distinguished Professor in the Department of Pharmacology and Toxicology and senior associate dean for diversity and inclusion in the Jacobs School of Medicine and Biomedical Sciences at UB.
“No one was thinking that the melatonin system was affected by these compounds, but that’s what our research shows,” she said.
Carbaryl is the third-most widely used insecticide in the U.S., but is illegal in several other countries. Carbofuran has been banned in the U.S., however is used in Mexico and other countries. Traces of carbofuran are persistent in wildlife, plants, and food.
Carbaryl is commonly sold under the tradename Sevin.
“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 homeostasis and insulin secretion,” said Marina Popevska-Gorevski, co-author, now a scientist with Boehringer Ingelheim Pharmaceuticals, who worked in Dubocovich’s lab while earning her master’s degree at UB. “That means that exposure to them could put people at higher risk for diabetes and also affect sleeping patterns.”
“By directly interacting with melatonin receptors in the brain and peripheral tissues, environmental chemicals, such as carbaryl, 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 Dubocovich.
For example, she explained, there is a fine balance between the release of insulin and glucose in the pancreas at very specific times of day, but if that balance becomes disrupted over a long period of time, there is a higher risk of developing diabetes.
Published online on Dec. 27 in Chemical Research in Toxicology, the research combined a big data approach, using computer modeling on millions of chemicals, with standard wet-laboratory experiments. It was funded by a grant from the National Institute of Environmental Health Sciences, part of the National Institutes of Health.