Early plasticizer exposure tied to adult anxiety in male rats
Researchers reported that male rats exposed to DEHP around birth showed more anxiety-like behavior as adults, with effects eased by GABA agonists or testosterone.
By Lucas Ferreira · Science & Environment Writer
3 min read
Male rats exposed to a common plastic additive before birth and during early life showed more anxiety-like behavior as adults, according to research presented at ENDO 2026 in Chicago. The finding matters because DEHP is widely used in flexible plastic products, though the work was done in rodents and does not prove the same effect in people.
The Endocrine Society said the study examined di-(2-ethylhexyl) phthalate, or DEHP, a plasticizer added to make products more pliable. The chemical is used in items including medical devices, toys, shower curtains and raincoats.
Researchers at the University of Buenos Aires School of Medicine tested whether early exposure to DEHP could alter anxiety-related behavior later in life. They also examined whether two hormone and brain-signaling pathways, involving gamma-aminobutyric acid, known as GABA, and testosterone, were connected to the observed effects.
How the study was conducted
In the experiment, pregnant female rats received DEHP by mouth each day starting on the first day of pregnancy. The dosing continued until their pups were weaned, according to The Endocrine Society.
When male offspring reached adulthood at 70 days old, the researchers evaluated their behavior in an elevated plus maze. The test uses a raised, plus-shaped maze with two open arms and two enclosed arms, relying on rodents’ tendency to avoid exposed spaces and heights.
The team recorded how often the rats entered open or enclosed arms, how much time they spent in each area and how long they remained still. That stillness, known as freezing time, is commonly used as a sign of anxiety-like behavior in rodents.
What researchers found
Male rats exposed only to DEHP during development were less willing to spend time in the open arms of the maze, according to the researchers. They spent more time in the enclosed arms and showed more freezing behavior.
Some animals received GABA agonists, compounds that bind to and activate GABA, 90 minutes before maze testing. Other animals were treated with testosterone every 48 hours for 14 days before the test.
The Endocrine Society said DEHP-exposed rats given either GABA agonists or testosterone showed the reverse behavioral pattern from rats exposed only to DEHP. The researchers interpreted that result as evidence that the treatments countered the anxiety-related changes associated with early DEHP exposure.
Osvaldo Juan Ponzo, a professor of physiology at the University of Buenos Aires School of Medicine, said the work indicates that exposure during prenatal and immediate postnatal development can produce behavioral changes that persist over time. He also said the findings suggest those neuroendocrine changes can be reversed with GABA agonists or testosterone.
Limits of the findings
The study adds to prior research cited by The Endocrine Society showing that DEHP and its breakdown products can affect several organ systems in animals and humans, including the reproductive and nervous systems. The new findings focus on adult male rats after early-life exposure.
The Endocrine Society said the rodent results suggest endocrine-disrupting chemical exposure before and shortly after birth could potentially lead to long-lasting behavioral changes in humans. The study, however, was not a human trial, and the reported behavioral effects were measured in a laboratory test designed for rodents.
This story draws on original reporting from ScienceDaily.