A new study in mice suggests that a drug that blocks a receptor for NPY increases heat generation in fat tissue. In animals fed a high-fat diet, the drug reduced weight gain by around 40%.
The drug does not appear to cross the blood-brain barrier, so unlike other weight loss drugs, it is unlikely to adversely affect mood.
According to the World Health Organization (WHO), the prevalence of obesity worldwide has more than tripledTrusted Source since 1975.
In 2016, the WHO estimates, 39% of all adults worldwide were overweight, and 13% had obesity. These conditions are associated with diabetes, cardiovascular disease, and some cancers.
Changing exercise and dietary habits can help people reach and maintain a healthy weight. However, taking these steps effectively can be challenging for many reasons, and some people also look to appetite-suppressing medication.
Over the years, various drugs that suppress the appetite by acting directly on neurotransmitter systems in the brain have been withdrawn from the market due to adverse effects, particularly involving mood and the function of the heart.
“Most current prescribed treatments are aimed at reducing food intake by targeting the central nervous system,” says Dr. Yanchuan Shi, who leads the neuroendocrinology group at the Garvan Institute of Medical Research, in Sydney, Australia.
“However, these can have significant psychiatric or cardiovascular side effects, which have resulted in over 80% of these medications being withdrawn from the market,” she notes.
Dr. Shi and colleagues wanted to test a new way of reducing weight gain without affecting the central nervous system. Their research has been published in Nature Communic-ationsTrusted Source.
The team focused on a nerve signaling molecule called NPY. It helps many animals, including mice and humans, survive conditions in which food shortages are commonplace.
NPY increases food intake and conserves energy stores by reducing heat generation in a type of fat tissue called brown adipose tissue.
In an environment where people have ready access to food and do not get sufficient exercise, however, NPY may make it particularly difficult to lose weight.