Leptin is a hormone that controls the percentage of fat stored in the body. According to a new study by Monash University and the University of Cambridge the hormone also increases the amount of blood pressure that occurs with weight gain. Leptin is produced by fat and circulates in the bloodstream to reach the brain, where it acts as a signal for energy reserves, regulating both energy expenditure and the sensation of hunger.
The study published in the journal Cell has illustrated a more detailed link between high blood pressure and obesity. Obesity or being overweight is a major risk factor for the development of high blood pressure and cardiovascular disease.
Mice models and humans were used for this study. A group of individuals with problems producing or processing the hormone leptin was compared with ‘healthy’ individuals to see whether this hormone could provide the link.
The research revealed that some obese people who lacked the leptin hormone as a result of a genetic disorder, also had low blood pressure despite being very heavy. This was also the case for people lacking the gene for the leptin receptor in the brain, as the brain was unable to process the hormone.
Mice with normal leptin signalling developed an increase in blood pressure when they became obese on a high fat diet. These effects were not seen in mice that lacked leptin or where leptin was unable to work because of a defect or block on the leptin receptor.
The research findings revealed that leptin signalling is necessary for obesity-induced increased blood pressure.
“High blood pressure is a well-known consequence of obesity. Our study explains the mechanism behind this link, showing that leptin, a hormone secreted by fat, increases blood pressure,” said Professor Cowley.