Single-cell spatial transcriptomic atlas of the mouse adrenal gland reveals sexual dimorphism in steroidogenic enzyme and hormone receptor expression.

Abstract

The adrenal cortex shows sexual dimorphism in structure and function. We analysed adrenal glands from 7-week-old male and female BALB/c mice using Visium HD with Cellpose 3 segmentation, comprising 236,077 cells across eleven populations, including four cortical zones. Using curated marker-gene-based zonal annotation, we focused on steroidogenic enzymes and hormone receptors, complementing our companion study based on the same primary dataset. The X-zone was nearly absent in males but prominent in females. Females showed higher Hsd3b1 expression across cortical zones and higher Cyp11b1 expression in outer cortical compartments. The strongest sex difference involved Srd5a2, with markedly higher expression in male zona fasciculata (inner: 77.1% vs. 28.9%), independently supported by RNAscope and immunohistochemistry. Mc2r and Mrap showed discordant spatial distributions, with limited co-expression, suggesting potential MC2R-independent MRAP roles. Agtr1a dominated angiotensin II receptor expression in zona glomerulosa without major sex differences, providing a zone-resolved reference for adrenal sexual dimorphism.