In a groundbreaking advance that promises to reshape our understanding of metabolic and psychiatric disorders, researchers at the Icahn School of Medicine at Mount Sinai have unveiled the first comprehensive sex-specific atlas mapping the distribution of glucagon-like peptide 1 (GLP-1) in the mouse brain at single-transcript resolution. This study, published on March 10, 2026, in the peer-reviewed journal Brain Medicine, delineates the intricate landscape of GLP-1 expression across 25 distinct brain nuclei, subnuclei, and regions, revealing stark differences between males and females that could illuminate sex-specific disease mechanisms and therapeutic responses.
GLP-1 analogs such as semaglutide, liraglutide, and lixisenatide have revolutionized the management of obesity and diabetes, transforming these conditions with unprecedented efficacy in appetite suppression, glycemic control, and weight management. Yet, despite the clinical success and widespread use of these drugs, fundamental questions have lingered: Where exactly does GLP-1 reside in the brain, and do its patterns of expression differ between sexes? By harnessing superior molecular imaging techniques, this research offers a decisive answer.
The team leveraged RNAscope, a cutting-edge in situ hybridization technology capable of detecting individual mRNA transcripts with exceptional specificity and sensitivity. This approach allowed them to precisely localize Glp1 gene expression in coronal whole-brain sections, only 5 microns thick, from both female and male murine subjects. The method’s high resolution and specificity overcame previous technological limitations associated with the low abundance and rapid degradation of GLP-1 in neural tissue, enabling a robust, sex-specific neural transcriptomic atlas.
Analyses revealed that GLP-1 is not uniformly distributed in the brain but exhibits a complex, sexually dimorphic pattern. While the medulla and olfactory bulb harbored the highest concentrations of Glp1 transcripts in both sexes, key differences emerged within subregions. Females showed peak GLP-1 expression in hindbrain territories such as the raphe obscurus nucleus (ROb), ventral, and medial parts of the nucleus of the solitary tract (SolV and SolM). In contrast, male mice exhibited higher GLP-1 densities in the central and intermediate solitary tract nuclei (SolCe and SolIM). Statistically significant elevated expression in the SolV of females underpinned potential mechanisms for female-biased efficacy of GLP-1 drugs.
The sex-specific expression in the hindbrain suggests differentiated neurocircuitry and peptide signaling that may underlie sex differences observed clinically in appetite regulation and metabolic control. Indeed, several medullary nuclei with GLP-1 expression were sex-exclusive: the ambiguus nucleus and ventral cochlear nucleus only in females, while males uniquely expressed GLP-1 in the dorsomedial spinal trigeminal and paramedian reticular nuclei, among others. These findings open an exciting avenue for investigating sex-specific neural pathways targeted by GLP-1 analogs, with implications for tailored therapeutics.
Unexpectedly, the olfactory bulb exhibited striking sexual dimorphism in GLP-1 levels. Male mice demonstrated significantly higher GLP-1 expression, particularly in the granular cell layer, a region implicated in modulating olfactory-driven satiety signals. This discovery aligns with emerging evidence that post-prandial olfactory stimuli and cephalic phase insulin release are more pronounced in males. Conversely, female mice’s enhanced estrogenic modulation of olfactory circuits could compensate for their comparatively lower GLP-1 levels in this region, suggesting a nuanced interplay between peptide signaling and sex hormone regulation.
Beyond metabolism, the atlas maps GLP-1 presence in brain regions integral to reward processing, motivation, and cognition. For example, the ventral tegmental area (VTA)—a central node in dopaminergic signaling related to reward and addiction—expressed GLP-1 only in females, while the lateral hypothalamus showed male-specific GLP-1 expression. This sexually dimorphic neurochemical milieu implicates GLP-1 in psychiatric and neurodegenerative diseases, supporting burgeoning evidence that GLP-1 analogs might modulate neuroinflammation, neurodegeneration, and cognitive deficits, including those occurring in Alzheimer’s disease.
These insights must be contextualized within a broader framework of peptidergic regulation of appetite and behavior, where multiple systems interplay. Notably, females generally exhibit lower hypothalamic neuropeptide Y (NPY) but higher anorexigenic pro-opiomelanocortin (POMC) neuron activity, with estrogen receptor alpha modulating POMC-mediated food intake suppression in females. Leptin signaling, ghrelin counterbalance, and serotonergic projections from GLP-1 axon terminals in the ROb collectively orchestrate a sophisticated neurochemical ballet that is distinctly calibrated in each sex.
The construction of this atlas is predicated on rigorous experimental design. Three female and three male mice were analyzed with blinded, manual counting of RNA transcripts every tenth section to ensure reliability and minimize bias. Validation controls included tissues known to express or lack GLP-1, confirming probe specificity. Despite the high-resolution mapping, the authors acknowledge limitations stemming from relatively limited sample size, lack of estrous cycle staging in females, and RNAscope’s detection of mRNA rather than direct peptide quantification, signaling the need for functional and behavioral correlation studies.
The implications of this atlas extend far beyond the laboratory bench. With GLP-1-based drugs increasingly prescribed worldwide, understanding the anatomical bases for sex differences in drug response can enhance precision medicine strategies, optimizing efficacy and minimizing side effects. Furthermore, the conservation of preproglucagon neuron distribution between rodents and primates offers translational relevance, heralding potential breakthroughs in treating not only metabolic disorders but also psychiatric conditions and neurodegenerative diseases.
In sum, this comprehensive sex-specific GLP-1 expression atlas is a landmark resource, establishing foundational knowledge that bridges molecular neuroanatomy with clinical applications. This work transforms an intuitive understanding of peptide action into a mechanistic framework, providing an indispensable tool for researchers and clinicians exploring the multidimensional roles of GLP-1 in health and disease. As therapies advance, this atlas will be instrumental in unraveling the complex sex-dependent neural circuits that govern metabolism and behavior.
The research article, entitled “Atlas of GLP-1 expression in the mouse brain: Neuroanatomical basis for metabolic and psychiatric effects,” is openly accessible through Brain Medicine (DOI: https://doi.org/10.61373/bm026a.0006), inviting the scientific community to delve into this rich neuroanatomical dataset and explore its vast implications.
Subject of Research: Animals
Article Title: Atlas of GLP-1 expression in the mouse brain: Neuroanatomical basis for metabolic and psychiatric effects
News Publication Date: 10 March 2026
Web References: https://doi.org/10.61373/bm026a.0006
References: Ryu V, Gumerova A, Pevnev G, Yuen T, Zaidi M. Atlas of GLP-1 expression in the mouse brain: Neuroanatomical basis for metabolic and psychiatric effects. Brain Medicine. 2026. DOI: https://doi.org/10.61373/bm026a.0006
Image Credits: Mone Zaidi
Keywords: GLP-1, glucagon-like peptide 1, sex differences, RNAscope, mouse brain atlas, obesity, diabetes, neuropeptides, metabolism, psychiatric disorders, neuroanatomy, neurodegeneration
Tags: appetite suppression neural pathwaysglucagon-like peptide 1 expression in mouse brainglycemic control sex differencesliraglutide brain distributionlixisenatide neural localizationmetabolic disorder sex-specific mechanismspsychiatric disorders and GLP-1RNAscope mRNA detection technologysemaglutide effects by sexsex differences in weight-loss drug responsesex-specific GLP-1 brain atlassingle-transcript resolution brain mapping
