Scientists at Northwestern University discovered that male and female brains react differently to some medications, yet 85 percent of preclinical drug trials are performed only on male animals.
For years now, scientists have been researching and testing treatments for humans in general. But researchers at Northwestern University just made a groundbreaking discovery: drugs react differently in male and female brains due to a difference in the molecular structures.
Specifically, the difference occurs in the regulation of synapses in the hippocampus—the brain region involved in learning, memory, and responses to stress and epilepsy. Some drugs, like endocannabinoids, target synaptic pathways, which would account for the different reactions in men and women. Scientists have long wondered why some brain disorders vary between the sexes, and this could finally offer an explanation.
Catherine Woolley, neurobiology professor at Northwestern University and senior author of the study published in the Journal of Neuroscience, said that she’d avoided studying sex differences in the brain until her own data proved the differences were significant. In 2012, she discovered that estrogens had an effect in the brains of female rats but not in males, and this changed her thinking. In a press release, Woolley states, “Being a scientist is about changing your mind in the face of new evidence.”
In the most recent study, Woolley and her team discovered that a drug that regulates an important molecule in neurotransmitter release (URB-597) had an effect in females but not in males. The drug and others like it are currently being tested in clinical trials in humans, so the findings could have huge implications. Woolley suspects that the researchers investigating endocannabinoids in humans probably aren’t aware that these drugs could have different effects in males and females.
In order to improve future diagnoses, treatments, and cures, scientists need to conduct separate studies of drug effects on each sex. About 85 percent of basic neuroscience studies are done in male animals, tissues, or cells, and it’s evident now that these studies could have rendered different results had the testing been extended to females as well.
“We are not doing women — and specifically women’s health — any favors by pretending that things are the same if they are not,” Woolley asserts. “If the results of research would be different in female animals, tissues, and cells, then we need to know. This is essential so that we can find appropriate diagnoses, treatments, and, ultimately, cures for disease in both sexes.”