Related Experiment Video
Updated: Mar 21, 2026
Comparative Proteomic Analysis of Whole Kidney, Medulla, and Cortical Tubules in Diabetic Pathogenesis of Kidney Injury in Mice
Published on: May 2, 2025
Bileomic identification and quantification of bile acids in rat kidney by UPLC-MS/MS
1Gaikwad Steroidomics Laboratory, 720 Olive Drive, Ste F, Davis, CA 95616, USA.
Background:
Bile acids (BAs) act as endocrine-like signals governing metabolic, inflammatory, oncologic, neurodegenerative, hepatic, and renal processes as well as cellular homeostasis. Despite renal expression of the BA receptors FXR and TGR5, direct demonstration of BAs in kidney tissue has remained elusive.
Objective:
To provide the first comprehensive identification and quantification of BAs in rat kidney using a mass spectrometry-based bileomics approach.
Methods:
Kidneys from female Wistar rats (n = 6) were profiled by ultra‑performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) with Multiple Reaction Monitoring for BA panel. Data were processed in TargetLynx and analyzed by unsupervised principal component analysis (PCA) to compare kidney with urine.
Results:
Approximately 20 BAs were identified in kidney tissue. The composition was dominated by amidated species (69.4%), followed by non‑amidated (30.4%) and trace glycine-conjugated species (∼0.1%). Taurine conjugation predominated over glycine. CA, TCA, and T‑β‑MCA were the most abundant species. PCA revealed a distinct kidney BA profile compared with urine, ruling out contamination and confirming tissue‑resident BAs.
Conclusions:
This is the detailed report of a kidney tissue bileome. The distinct BA signature suggests active transport, metabolism, and signaling functions in kidney and provides a foundation for mechanistic studies of BA‑mediated renal physiology and disease.
