A Ghrelin Receptor Variant Promotes Fat Storage by Changing How Nutrients Are Partitioned | Research

The takeaway

The GhsrQ343X allele favors fat storage over lean mass by acting on nutrient partitioning through the constitutively active ghrelin receptor, independent of ghrelin hormone levels.

Fat storage without hunger
This GHSR variant promotes fat storage not by increasing appetite but by changing how the body distributes nutrients — a ghrelin-independent metabolic effect

What the researchers found

GhsrQ343X allele alters nutrient partitioning to favor fat storage through constitutive GHSR activity, independent of ghrelin-mediated effects. Demonstrates that GHSR baseline signaling independently regulates metabolic programming.

Why it matters

Understanding why some people store fat more easily despite similar diets could explain individual obesity susceptibility. GHSR constitutive activity — without ghrelin — may be an underappreciated driver of body composition.

The numbers in context

GhsrQ343X mutation; preferential CHO oxidation; no change in intake/expenditure/activity; increased LEAP2:ghrelin ratio; increased hypothalamic Ghsr

How the study worked

Genetic and metabolic study. GhsrQ343X allele characterization. Nutrient partitioning analysis. Fat vs lean mass composition. Constitutive GHSR activity assessment independent of ghrelin.

Who was studied

GhsrQ343X mutant rats vs. wild-type littermates

What this study cannot tell us

Genetic variant study — population frequency and clinical impact need characterization. Mechanistic details of nutrient partitioning not fully elucidated. Translation from model to human phenotype needs confirmation.

How to read the evidence

Moderate evidence: genetic study with metabolic phenotyping demonstrating constitutive GHSR activity effects on nutrient partitioning.

When this study was published

Published 2021. GHSR constitutive activity research continues as a distinct pharmacological target.

The bigger picture

GHSR constitutive activity is emerging as important as ghrelin-mediated activation. Drugs targeting constitutive GHSR activity (inverse agonists) could address obesity independently of ghrelin signaling.

Questions still open

How common is the Q343X allele in human populations?
Could GHSR inverse agonists prevent excess fat storage in carriers?
Does this explain some cases of obesity-resistant thinness or obesity-prone weight gain?

Common questions

Can your genes make you store more fat?

Yes — this study shows a variant in the ghrelin receptor gene changes how the body partitions nutrients: more toward fat and less toward lean tissue. This occurs even without changes in appetite or food intake, through the receptor's baseline (constitutive) activity.

What is constitutive receptor activity?

Most receptors sit idle until a hormone activates them. The ghrelin receptor is unusual — it's partially active even without ghrelin. This baseline activity affects metabolism independently. The Q343X variant alters this baseline, shifting the body toward fat storage.

Read the original research

The GhsrQ343X allele favors the storage of fat by acting on nutrient partitioning.

The Journal of endocrinology, 251(3), 181–194

View on PubMed ↗Publisher’s paper ↗

Citation

Marion, Candice; Zizzari, Philippe; Denis, Raphaël G P; Hassouna, Rim; Chebani, Yacine; Leste-Lasserre, Thierry; Doat, Hélène; Le Pen, Gwenaëlle; Cota, Daniela; Noble, Florence; Luquet, Serge; Pantel, Jacques. (2021). The GhsrQ343X allele favors the storage of fat by acting on nutrient partitioning.. The Journal of endocrinology, 251(3), 181–194. https://doi.org/10.1530/JOE-20-0576