SAN DIEGO — Early exposure to low doses of hormone-disrupting chemicals may alter gene expression in the liver and liver function, thereby increasing susceptibility to obesity and other metabolic diseases later in life, according to a new study presented at ENDO 2015.
In an animal study, researchers found that similar to developing tissues of the reproductive tract, neonatal exposure to bisphenol A (BPA) during critical developmental periods can activate nongenomic signaling in the neonatal liver that is associated with reprogramming of the adult liver, altered liver metabolism and function.
Senior study investigator, Cheryl Lyn Walker, PhD, who is the director of the Texas A&M University Health Science Center Institute of Biosciences and Technology in Houston, said even a short exposure to these endocrine disruptors at the wrong time of development has a lifelong effect on the individual.
For their study, Dr. Walker and her colleagues focused on the liver and gave groups of newborn rats low doses of one of four different endocrine disruptors (BPA, genistein [GEN], diethylstilbestrol [DES] or tributyltin [TBT]) during a critical period of liver development (3 days immediately after birth). They examined liver tissue from these chemically exposed animals either immediately after exposure or 70 days later when the rats were adults. They compared liver samples to those obtained from unexposed control rats.
BPA and another endocrine disruptor, TBT (an additive in paint and textiles) caused liver damage consistent with human nonalcoholic hepatic steatosis. Analysis of liver gene expression patterns of the exposed rats found that the endocrine disruptors induced developmental reprogramming of the animals’ epigenomes.
“We know that environmental exposures early in life can increase the likelihood we will develop certain diseases as adults, including obesity. While studies on this type of developmental programming have focused primarily on fat cells and the pancreas, the liver, which is the main source for glucose production in the body, has been overlooked,” Dr. Walker told Endocrinology Advisor.