Insecticides May Lead to Diabetes, Metabolic Diseases

Disruptions in circadian rhythm can alter the release of insulin and glucose, causing diabetes.

A recent study found that chemicals in most insecticides and garden products affect receptors that control circadian rhythm.

Exposure to these products was observed to affect melatonin receptors, and increase the risk of developing metabolic diseases, such as diabetes, according to a study published by Chemical Research in Toxicology.

The researchers used a combination of big data, computer modeling of millions of chemicals, and wet-laboratory experiments to discover these changes in circadian rhythm.

Altered circadian rhythm is known to increase the risk for diabetes, metabolic diseases, and can even cause cancer in some patients. Unfortunately, the mechanisms involved with this are currently unknown.

“This is the first report demonstrating how environmental chemicals found in household products interact with human melatonin receptors,” said senior author on the paper Margarita L. Dubocovich, PhD. “No one was thinking that the melatonin system was affected by these compounds, but that’s what our research shows.”

The investigators focused their effort on 2 different chemicals included in insecticides. The first was carbaryl, which is illegal in some countries, but is the third most used insecticide in the United States, according to the study. The second was carbofuran, which is the most toxic insecticide, and has been banned from use on food since 2009. However, carbamate insecticides are still used in Mexico, and other countries that the United States imports food from.

“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 co-author Marina Popovska-Gorevski, MSc. “That means that exposure to them could put people at higher risk for diabetes and also affect sleeping patterns.”

These findings suggest a need to evaluate whether environmental chemicals can alter the circadian rhythm, according to the study.

This study is part of a larger research initiative that aims to identify harmful chemicals that alter melatonin.

“Our approach seamlessly integrates the screening of environmental chemicals through computer simulation, in vitro and in vivo techniques to gauge the risk these chemicals present for various disease end points,” said lead study author Raj Rajnarayanan, PhD.

The researchers have a database that contains approximately 4 million chemicals that are reported to be toxic.

“From those, we identified hundreds of thousands of compounds that had readily available chemical structures so that we could study them,” Dr Rajnarayanan said.

The researchers then grouped chemicals by similarity, which revealed that several groups were similar to melatonin. Through computer and in vitro experiments, they found that carbamates selectively interact with the melatonin receptor, which then disrupts important regulatory processes, according to the study.

“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,” Dubocovich said.

The release of insulin and glucose in the pancreas is specific to the time of day. If this is disrupted, patients are at a higher risk of developing diabetes, according to the study.

Although federal regulators are not exploring this occurrence, the researchers are currently working to create a rapid bioassay that can determine if other chemicals can affect circadian rhythm similarly to the 2 insecticides, the study concluded.