This one organ changes its sex during illness, experiment reveals

It turns out that biology is much more sophisticated than we ever imagined. An experiment conducted on mice revealed that an organ changes its sex during illness.

 Liver diagram (photo credit: Wikimedia Commons)
Liver diagram
(photo credit: Wikimedia Commons)

We never thought we’d write this but the human body holds many surprises. A new study from the University of Queensland in Brisbane, Australia found that the male liver can change to female in response to disease, probably as a physiological response of self-defense.

This amazing finding is described in a new article published in the journal PNAS, which used a mouse model to study the effect of turning off genes associated with the biological clock to see how the body responds to changes in diet.

This unexpected finding came as a surprise, as the researchers set out to find insights into why a disruption in sleep patterns is associated with metabolic and liver diseases, and during these investigations the surprising sex change became clear.

Study editor Dr. Frederic Gachon of the University of Queensland's Institute of Molecular Bioscience said that "When mice were fed a high-fat diet after their biological clocks were shut off, we expected them to develop diabetes or non-alcoholic fatty liver disease (NAFLD) like the mice in the control group, but they didn’t. He added that "We also found that the livers of obese male mice became female, probably due to the protective nature of the female sex hormone estrogen."

Similar to our reproductive organs, the liver has a sexual dimorphism, meaning that there are distinct characteristics in the livers of males and females. This includes broad differences in their gene profiles, with more than 1000 genes in the liver being gender-specific.

 Liver diagram (credit: Wikimedia Commons) Liver diagram (credit: Wikimedia Commons)

There are other interesting details about the liver. It’s the second heaviest organ in the human body, after the skin system and before the brain. It functions as the largest gland and weighs about 1500 grams. Also, it has a reddish-brown color because it contains a large amount of blood;1.4 liters of blood flow through it every minute.

Curious to see if the transformation of the liver into a “female” seen in mice applied to humans, the team tested human samples and found it did. In fact, human liver tissue revealed not only that "feminization," as it was called by researchers, was linked to liver disease, but that it progressed as the disease worsened. "It seems that disrupting the rhythm of the biological clock may protect the liver by changing hormone levels such as growth hormone, estrogen, and testosterone," Gachon said.

Combining the findings of the mouse and the human findings, the study authors believe that the biological clock can play a role in slowing the progression of the disease by tuning metabolic pathways. "In light of these findings, we’re investigating if behavioral and hormonal interventions might be possible treatments for liver disease," Gachon concluded.