CHICAGO, ILL. — Researchers at the University of Buenos Aires School of Medicine presented a study on di-(2-ethylhexyl) phthalate at ENDO 2026, the Endocrine Society's annual meeting. The study indicated that prenatal and postnatal exposure to DEHP causes lasting anxiety-like behaviors in male rats.

DEHP is a chemical additive that increases the flexibility of plastic items such as medical devices, toys, and raincoats. Previous research has shown that this chemical and its metabolites interfere with reproductive and nervous systems in animals and humans.

For the study, pregnant female rats received daily oral doses of DEHP from the first day of gestation until their pups were weaned. Researchers then evaluated anxiety-like behaviors in male offspring at 70 days of age using an elevated plus maze test.

The elevated plus maze test measures rodent avoidance of open spaces and heights, consisting of two open and two enclosed arms shaped like a plus symbol. Male rats exposed exclusively to DEHP spent less time exploring open maze arms, more time in enclosed arms, and demonstrated increased motionless freezing time.

Some test subjects received gamma-aminobutyric acid (GABA) agonists 90 minutes before maze evaluation. Other test subjects received testosterone treatments every 48 hours for 14 days prior to maze evaluation. DEHP-exposed rats treated with GABA agonists or testosterone displayed behavioral patterns that counteracted the anxiety-like responses observed in untreated exposed rats.

Osvaldo Juan Ponzo, a professor of physiology at the University of Buenos Aires School of Medicine, said. "This research demonstrates that one of the most widely used plasticizers worldwide is capable of causing behavioral changes when the subject is exposed during the prenatal and immediate postnatal developmental stages, with this effect lasting over time." Ponzo added, "This work demonstrates that contact with DEHP in the early stages of life could modify behavior with regard to anxiety, even in the absence of DEHP exposure in adulthood." He said, "These neuroendocrine changes can be reversed by treating with GABA agonists or testosterone."