Phthalate exposure in early life may lead to anxiety in adult male rats
Endocrine-disrupting chemical DEHP increases flexibility of plastic products
The Endocrine Society
Chicago—Male rats that were exposed to the widely used plasticizer di-(2-ethylhexyl) phthalate (DEHP) during early development exhibited increased anxiety behavior as adults, according to a study being presented Saturday at ENDO 2026, the Endocrine Society’s annual meeting in Chicago, Ill.
While the research was performed in rodents, the work suggests humans exposed to endocrine disruptors before and shortly after birth may experience behavioral changes that last a lifetime.
“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,” said Osvaldo Juan Ponzo, M.D., Ph.D., professor of physiology at University of Buenos Aires School of Medicine in Buenos Aires, Argentina.
DEHP is used in many plastic items to make them more flexible, such as medical devices, toys, shower curtains and raincoats. Numerous studies have shown that DEHP and its metabolites interfere with a number of organ systems in animals and humans, namely the reproductive and nervous systems. Scientists at the University of Buenos Aires School of Medicine wanted to examine the effects of DEHP on anxiety-like behavior in adult male rats and determine whether the inhibitory neurotransmitter gamma-aminobutyric acid (GABA) or testosterone was involved in regulating this action.
Pregnant female rats were given DEHP orally every day, starting with the first day of gestation until they weaned their litter. After male pups reached maturity at 70 days old, the research team evaluated their anxiety-like behaviors by placing them in an elevated plus maze (EPM), a test based on the natural aversion of rodents to open spaces and heights. The EPM is shaped like a plus symbol and has two open and two closed arms. The scientists could gauge how often and how long the rats stayed in both arms, as well as how long they remained motionless, known as freezing time.
Ninety minutes before EPM testing, some of the animals were treated with GABA agonists—molecules that bind and activate GABA—while other animals received testosterone every 48 hours for 14 days prior to the test. The scientists observed that the DEHP-only group demonstrated anxiety-like behavior, spending less time exploring open arms and more time in the closed arms of the maze. They also had increased freezing time. However, the DEHP rats treated with GABA agonists and testosterone displayed the opposite characteristics.
"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," Ponzo said. "These neuroendocrine changes can be reversed by treating with GABA agonists or testosterone."
EDCs found in breast milk and infant urine up to age 6 months
Chemical exposure can interfere with hormones during baby’s development
Chicago—Endocrine-disrupting chemicals (EDCs) that interfere with hormones were found in breast milk and in the urine of children from birth up to 6 months, according to a study being presented Saturday at ENDO 2026, the Endocrine Society’s annual meeting in Chicago, Ill.
“Breast milk is the optimal nutritional source for any child and must be protected as it is a vehicle of environmental contaminants,” said Maria Elisabeth Street, M.D., Ph.D., associate professor and Director of the Division of Pediatric Endocrinology at the University of Parma and University Hospital of Parma, Parma, Italy. “Infancy represents a critical window of exposure since effects are magnified at this age with damage becoming evident after many years.”
Street and colleagues used data from 336 mother-infant pairs enrolled in the LIFE-MILCH project. Samples were collected one month, three months, and six months after birth.
The researchers measured exposure to more than 50 different chemicals, including bisphenols (BPA), polycyclic aromatic hydrocarbons, phthalates and metabolites, parabens, polar pesticides and pyrethroids.
BPA was commonly found in breast milk one month after birth (51.2%) and at six months postpartum (49.8%). Nearly a third of the infants had BPA in their urine samples following birth. The number increased to 67.6% when the infants were 6 months old.
Bisphenol S (BPS) was found in breast milk one month after birth (10.7%), at six months after birth (18.3%), and in infant urine samples at birth (22.4%) and at six months after birth (41.2%).
Most polycyclic aromatic hydrocarbons were rarely detected in breast milk, but several were consistently found in urine (up to 27.7%).
Methylparaben (MePB) and ethylparaben (EtPB) were most commonly found one month (51.2%; 42.3%) and six months postpartum (56.2%; 52.6%) in breast milk, and increased in urine samples over time.
Glufosinate was detected in breast milk one month after birth (27.4%) and three months (31.9%) after birth, and in urine samples at birth (44.7%) and at six months of age (38.2%).
Phthalates, including dibutyl phthalate (DBP), were found in 90.2% of breast milk samples at one month postpartum and 86.5% at six months postpartum. Levels in urine samples increased from 30.3% at birth to 79.4% at 6 months of age.
Most EDCs found in breast milk and urine samples are associated with nutrition habits and products used for personal and household care, Street said.
Studies found exposure to these chemicals were linked to neurodevelopmental issues, hormonal activation at birth, and androgenization, or the development of male reproductive characteristics. EDC exposure also can alter growth, weight and obesity, Street said.
The study findings have led to a prevention campaign with results currently under evaluation, and several stakeholders have signed agreements to monitor and reduce these chemicals in their products in Italy, Street said. The researchers urge public health officials to reduce exposure to EDCs and create preventive strategies to protect breast milk in a changing world.
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