New study may change how we think about GLP-1

Good news! However, the study is only about female mice! That is a little weird!

"... How does Ozempic actually  work?

In a new study, Yale researchers uncovered a previously unrecognized mechanism that challenged the classic idea of how Ozempic works. Rather than only suppressing appetite, they found that chronic GLP-1 treatment also recruits hunger neurons, triggering metabolic adaptations that contributes to fat loss, similar to what normally happens when the organism is under calorie deficiency. ..."

From the abstract:

"Significance

Glucagon-like peptide-1 receptor agonists (GLP-1RAs), including semaglutide, are highly effective antiobesity drugs, yet how the brain sustains their weight-lowering effects remains unclear.

Agouti-related peptide (AgRP) neurons are viewed as hunger-promoting cells opposing weight loss and are expected to be suppressed or bypassed by GLP-1RA therapy.

In female mice, AgRP neurons are recruited by GLP-1RA treatment and are required for its full weight-lowering effect. Disrupting AgRP function reduces the drug-induced body weight-lowering response, despite continued suppression of food intake. We identify glucocorticoid signaling as an important pathway linking GLP-1RA treatment to AgRP neuron recruitment. These findings suggest that hypothalamic AgRP neurons may not simply sustain hunger and oppose weight loss but can also support adaptive metabolic responses during GLP-1RA therapy.

Abstract

Glucagon-like peptide-1 receptor agonists (GLP-1RAs), including semaglutide, produce robust and sustained weight loss, yet the central mechanisms supporting their long-term efficacy remain incompletely understood.

Agouti-related peptide (AgRP) neurons of the arcuate nucleus are classically activated by negative energy balance and promote feeding and energy conservation. Based on this framework, GLP-1RAs have generally been expected to suppress or bypass AgRP neuron activity.

Here, we report that AgRP neuron activation is required for the full weight-lowering effects of GLP-1RAs in female mice.

Across complementary AgRP loss-of-function models, disruption of AgRP circuit integrity reduced the full weight-lowering effects of GLP-1RAs. This requirement varies with sex, diet, and mode of AgRP disruption.

We found that GLP-1RA treatment is associated with increased markers of neuronal activation, mitochondrial engagement, and synaptic remodeling in AgRP neurons.

We further identify a glucocorticoid-to-AgRP signaling axis as an important pathway mediating this functional recruitment of AgRP neurons.

Together, these findings reveal that contrary to prevailing assumptions, GLP-1RA engages AgRP neurons to sustain weight loss, highlighting an unexpected role for these neurons in coordinating adaptive metabolic responses to pharmacologically induced negative energy balance."

New study may change how we think about GLP-1s | Yale News "In a new study, Yale researchers identified an unexpected mechanism that challenges a long-held assumption about the brain’s hunger circuitry."

AgRP neurons are required for the weight-lowering effects of GLP-1 receptor agonists in female mice (no public access)

Diet context gates AgRP neuron involvement in Semaglutide-induced weight loss (preprint, open access)

Fig. 1 Female mice under Standard Diet require AgRP neurons for sustained weight loss and hypoglycemic effects.

Fig. 2 Sustained treatment with Semaglutide increases the activity of AgRP neurons.