In obese people there is an increase in activity of the renin-angiotensin system (RAS), which is inhibited by some drugs that treat hypertension. However, inhibiting the RAS does not lead to weight loss.
The RAS has a complicated role in metabolism; an increase in RAS activity in fat suppresses energy metabolism, while an increase in RAS activity in the brain increases metabolism.
Researchers at the University of Iowa found that angiotensin II type 2 receptors in fat are responsible for suppressing metabolism. They hypothesise that a leaky blood-brain barrier caused by obesity may allow RAS inhibitors to simultaneously suppress the RAS in both the brain and fat, preventing weight loss.
The authors, writing in Cell Reports (online, 28 July 2016)
, believe that this information could lead to the development of novel obesity-fighting drugs that inhibit the RAS specifically in adipose tissues.
 Littlejohn N, Keen H, Weidemann B et al. Suppression of resting metabolism by the angiotensin AT2 receptor. Cell Reports 2016;16:1–13. doi: 10.1016/j.celrep.2016.07.003