New Study Shows Liver Prepares for Food Before First Bite, Leading to Potential Treatment for Type 2 Diabetes

Your mouth doesn’t just water when you see delicious food. Your liver will also be active before the first bite. Scientists showed this Max Planck Institute for Metabolic Research after research on liver cells in mice.

The scientists found a mechanism that happens in our body when we are hungry and see or smell food. Within minutes of seeing food, the mitochondria (cellular powerhouses) in the liver cells change to prepare the liver for the upcoming meal. These cells are closely involved in sugar metabolism, the process that maintains the level of glucose in the blood (also known as blood sugar level). The insight could lead to new treatments for type 2 diabetes.

The researchers made this discovery after conducting experiments with mice that were hungry but could not eat. They fed the hungry mice while they monitored the cells in the liver. This showed that after only a few minutes, the mitochondria in the liver cells were already carrying out processes that were previously thought to be stimulated only by eating food. “We already knew that our body prepares to take food by producing saliva and digestive enzymes,” says researcher Sinika Henschke. “But we have now discovered how fast and how much the mitochondria in the liver cells change, even when no food has been ingested yet.”

The signal path
This preparation for eating begins with the POMC neurons: nerve cells in the hypothalamus that become active within seconds when they see and smell food. These nerve cells then send signals to the liver, as a signal for the mitochondria in the liver cells to prepare themselves for sugar metabolism. This is done by changing the protein in a process called ‘phosphorylation’ (see box). This phosphorylation then affects the liver’s sensitivity to insulin, a hormone that regulates blood sugar levels and is essential for a properly functioning body. Insulin ensures that glucose from food can be converted into energy.

What is phosphorylation?
Phosphorylation is a biochemical process in which a phosphate group (PO43-) is added to a molecule. This can happen with different molecules, such as proteins, carbohydrates and lipids. The addition of a phosphate group can greatly affect the structure and function of the molecule. In the case of proteins, phosphorylation is an important way to regulate activity. When a protein is phosphorylated, it can change shape, making it more or less active. Phosphorylation can also affect the binding of other molecules to the protein.

Type 2 diabetes
This finding is good news for diabetes patients. In people with type 2 diabetes, the body does not produce too much insulin and is less sensitive to insulin. So this signaling pathway may help to develop new treatments for this type of diabetes. According to Jens Brüning, lead author of the study, this research “shows the close connection between sensory perception of food, mitochondrial changes and insulin sensitivity.” ” He says that understanding these mechanisms is essential in the fight against type 2 diabetes, where insulin sensitivity plays an important role.

Currently, around 1.1 million Dutch people have type 2 diabetes but the condition is also common worldwide – and the numbers are increasing. In 2021, approximately 537 million people worldwide had type 2 diabetes. This is expected to increase to 783 million by 2045. Using the signaling pathway that affects mitochondria in the liver, scientists may be able to develop treatments that improve insulin sensitivity and regulate blood pressure. sugar levels.