Source: University of California – San Diego
Summary: Researchers reported, treating obese mice with catestatin (CST), a peptide naturally occurring in the body, showed significant improvement in glucose and insulin tolerance and reduced body weight.
In a normal human body, the liver helps regulate blood sugar by stimulating the body to absorb glucose as glycogen (for future use as energy). When sugar levels increase in the blood, the pancreas secretes insulin to decrease glucose production from the liver to maintain balance. When the liver stops responding to insulin, blood glucose levels rise, causing insulin production to go into overtime. If the body cannot maintain this heightened insulin production, the excess glucose leads to diabetes and other health disorders. Researchers from the University of California – San Diego treated an obese mice with catestatin (CST), a peptide naturally occurring in the body, which showed significant improvement in glucose and insulin tolerance and reduced body weight. The study findings were published in the journal Diabetes.
Treating obese mice with CST inhibited the recruitment of monocyte-derived macrophages to the liver and decreased inflammation, suggesting CST is an anti-inflammatory peptide. CST treatment also lowered blood sugar and insulin levels to normal and reduced fatty liver. Administering CST had no effect on insulin or glucose tolerance in control lean mice, showing that the effect of CST is restricted to obese animals. This difference may be explained by the reduced levels of normal CST in obese mice compared to the lean control animals. To confirm the importance of naturally occurring CST, the authors studied mice that lacked CST. These mice ate more and were heavier but lost weight when treated with CST. The researchers theorize that naturally occurring CST may help maintain body weight by suppressing hunger and enhancing glucose tolerance.
Prof. Sushil K. Mahata said, “The improved glucose and insulin sensitivity with CST treatment may be partly explained by the anti-inflammatory effects of catestatin on the liver”, “We have identified a novel pathway for suppression of liver glucose production that could be used to compensate for the loss of naturally occurring CST or to bolster its impact. But further studies are needed to uncover how CST suppresses liver inflammation to improve metabolism.”
More Information: Wei Ying et al, “Catestatin Inhibits Obesity-Induced Macrophage Infiltration and Inflammation in the Liver and Suppresses Hepatic Glucose Production Leading to Improved Insulin Sensitivity”, Diabetes (2018). DOI: 10.2337/db17-0788