Distinct brain regions mediate regulation of food intake in response to GIPR agonism or antagonism - Nature

What the report says

Nature reported a mouse study examining why both activation and blockade of the glucose-dependent insulinotropic polypeptide receptor, or GIPR, can contribute to weight loss when paired with GLP-1 receptor drugs. The work focused on two brain areas: the area postrema in the brainstem and the hypothalamus, using region-specific deletion of Gipr in mice to test effects on appetite, body weight and responses to metabolic drugs.

According to the paper, removing Gipr in the area postrema reduced mice’s responsiveness to the appetite-suppressing effects of a GIPR agonist, acyl-GIP. These mice also showed partial protection from diet-induced obesity on a high-fat diet, while the weight-loss effect of the GLP-1 receptor agonist liraglutide and the added effect of a GIPR antagonist were broadly similar to controls.

By contrast, mice lacking Gipr in the hypothalamus retained normal appetite suppression from acyl-GIP, but showed greater weight loss with liraglutide than control mice. In these animals, the additional weight-loss effect normally seen when a GIPR antagonist was combined with liraglutide was lost. The authors also reported that GIPR antagonism and hypothalamic Gipr deletion increased sensitivity to cagrilintide-induced weight loss.

The findings matter because drugs targeting GLP-1 and GIP pathways, including dual agonist approaches used in obesity and type 2 diabetes treatment, have raised unresolved questions about GIP’s mixed biology. The study suggests that GIPR agonism and antagonism may influence body weight through different neural sites, with the area postrema linked to appetite suppression from agonism and hypothalamic receptors implicated in antagonist-enhanced weight loss.