Research Identifies Hormone that May Cause Insulin Resistance and Type 2 Diabetes

Researchers from Kanazawa University in Japan have identified a hormone produced and secreted by the liver, which may be one of the causes of insulin resistance and Type 2 diabetes.

Hirofumi Misu, one of the researchers, said: “The current study sheds light on a previously underexplored function of the liver; the liver participates in the pathogenesis of insulin resistance through hormone secretion.”

The researchers had already discovered that genes encoding secretory proteins are expressed to a higher degree in the livers of people with Type 2 diabetes. The most recent discovery adds another piece to the picture: comprehensive gene expression analysis showed that the liver expresses higher levels of the gene responsible for encoding selenoprotein P (SeP) in people with Type 2 diabetes who are more resistant to insulin.

The connection between SeP seems to be causal, as studies in mice showed that SeP created insulin resistance and an increase in blood sugar levels. Blocking SeP in the livers of diabetic and obese mice improved their insulin sensitivity and successfully lowered blood sugar levels.

The findings furthermore suggest that SeP does not act independently. Fat tissues are a main contributor to insulin rsistance, as they produce fat-deprived hormones called adipokines. The results raise the possibility that “the liver functions as an endocrine organ by producing a variety of hepatokines”, and that “the disregulation or impairment of hepatokine production might contribute to the development of various diseases”.

The connection between SeP and adipokine will be the topic of further research.