The so-called "love hormone" could be a potential treatment for some people suffering from obesity and postpartum depression, researchers say.
Researchers are planning to develop new drugs based on oxytocin, known as the "love hormone", after achieving a "breakthrough" in discovering one of the genetic causes behind obesity and postpartum depression.
The researchers began their work by examining the genes of two boys from different families who were obese and also suffered from anxiety, autism and behavioral problems caused by sounds or smells.
They found that both boys were missing a single gene known as TRPC5, which is located on the X chromosome.
Further work found that the mothers of those children also lost the gene on one of their X chromosomes. Both mothers were obese and both suffered from postpartum depression.
The researchers, led by a team from the University of Cambridge and Baylor College of Medicine in Texas, USA, decided to further examine the missing gene in studies conducted on mice that had been genetically modified to contain a defective copy of the gene.
The researchers found that male mice carrying the defective gene showed the same problems as boys, including weight gain, anxiety, aversion to social interactions, and aggressive behavior.
Female mice showed similar behaviors. When they became mothers, they also showed depression-like behavior and "impaired childcare," the researchers said.
"What we saw in these mice was really cool," explained Dr. Young Xu of Baylor College of Medicine. "They showed behaviors very similar to those seen in people who lack the TRPC5 gene, which included signs of depression in the mothers and difficulty caring for their children. This tells us that this gene is causing these behaviors."
The researchers said the TRPC5 gene is part of a family of genes involved in detecting senses including temperature, taste and touch. The University of Cambridge noted that TRPC5 operates in the hypothalamus region of the brain, where it is known to control appetite.
When the researchers looked in more detail at this brain region, they discovered that TRPC5 acts on neurons that produce the hormone oxytocin.
Oxytocin is a type of hormone in the body that promotes positive feelings. Its primary function is to facilitate childbirth, but it has also been linked to increasing emotional bonding and can be released through touch, music, and exercise.
In the new study, the researchers found that deleting the TRPC5 gene from these oxytocin neurons led healthy mice to show signs of anxiety, overeating, poor social skills, and, in the case of mothers, symptoms resembling postpartum depression.
They found that "overexpressing" the TRPC5 gene in oxytocin neurons "reverses" these symptoms.
This suggests that restoring oxytocin could help treat people with missing or defective TRPC5 genes, which could lead to new treatments for obesity and postpartum depression, the researchers said.
“There is a reason why people who lack TRPC5 have all these conditions,” said Professor Sadaf Farooqi, from the University of Cambridge’s Institute of Metabolic Sciences. “We have long known that the hypothalamus plays a key role in regulating instinctive behaviours that enable humans and animals to survive, such as foraging, social interaction, the flight or fight response, and caring for their offspring. Our work shows that TRPC5 acts on oxytocin neurons in the hypothalamus to play a crucial role in regulating our instincts.”
“While some genetic conditions such as TRPC5 deficiency are very rare, they teach us important lessons about how the body works. In this case, we have made a major advance in understanding postpartum depression, a serious health problem about which very little is known despite many decades of research. More importantly, it may point to oxytocin as a potential treatment for some mothers with this condition,” she added.