The elusive link between obesity and high blood pressure has been pinned down to the action of leptin in the brain, and we might be able to block it with drugs.
We've known for more than 30 years that fat and high blood pressure are linked, but finding what ties them together has been difficult. One of the favourite candidates has been leptin – a hormone produced by fat cells.
Under normal circumstances, when fat cells produce leptin, the hormone sends the message that you've had enough food. But in people with obesity, the body stops responding to this message, and large levels of leptin build up.
Leptin is known to activate the regulatory network called the sympathetic nervous system, and it's the activation of sympathetic nerves on the kidneys that seem to be responsible for raising blood pressure. Leptin has thus been linked to blood pressure. However, conclusive evidence has been hard to come by.
No leptin, no problem
Michael Cowley of Monash University in Melbourne, Australia, and his colleagues have now conducted a string of experiments that provide some evidence. Through genetic and drug experiments in mice, they have pinpointed an area in the mouse brain that increases blood pressure when it is exposed to high leptin levels.
This region is called the dorsomedial hypothalamus, and is thought to be involved in controlling energy consumption. Their findings show that high levels in leptin do indeed boost blood pressure, via this brain region.
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