Lack of atrial natriuretic peptide in the Dahl SS rat results in systemic metabolic changes that uncover novel cross-organ metabolic pathways independent of dietary salt

Objective: Atrial natriuretic peptide (ANP) is a cardiac hormone that plays a crucial role in maintaining cardiovascular, renal, and metabolic homeostasis is a known regulator of blood pressure. Recent studies have reported that ANP deficiency is associated with obesity, insulin resistance, and cardiometabolic disease, however its metabolic functions in salt-sensitive hypertension are not well studied. Herein, we performed an integrated cross-organ metabolomics study to elucidate the impact of ANP knockout (KO). We hypothesized that lack of ANP results in a systemic mitochondria-driven metabolic phenotype that is independent of dietary salt. Ethics: Animal use and welfare were in accordance with the IACUC reviewed and approved protocol and Animal Research: Reporting of In Vivo Experiments guidelines. Methods: ANP knockout (KO) and wild-type (WT) male Dahl Salt-Sensitive rats were fed either normal-salt (0.4% NaCl, NS) or high-salt (4% NaCl, HS) diets for three weeks starting at 8 weeks of age, then the kidney cortex (n=8/group), urine (n=8/group), and heart (n=12/group) were collected for metabolomics analysis using liquid chromatography-high resolution mass spectrometry (Thermo Exactive Orbitrap). Two-way ANOVA (factors: genotype and diet) was used to identify metabolites driven primarily by the lack of ANP. Metabolites with significant main effects of genotype (FDR-corrected, FDR< 0.05) were interpreted using pathway-level integration. Results: Genotype was the dominant driver of metabolic profile differences in all tissues, demonstrating that ANP KO causes basal metabolic rewiring even in the absence of salt stress. Several findings represent previously unreported aspects of ANP biology. In the kidney, ANP KO rats showed a novel link between ANP signaling and glycosylation/NADPH metabolism with coordinated downregulation of the hexosamine biosynthesis pathway (p< 0.001) (UDP-N-acetylglucosamine, FC=-4.2; N-acetylglucosamine-1,6-phosphate, FC=-1.7) and pentose phosphate pathway (PPP) (sedoheptulose-7-phosphate, FC=-3.0). ANP KO also altered one-carbon metabolism (S-adenosyl-L-methionine, S-adenosyl-L-homocysteine, cystathionine), indicating impaired methylation capacity, and altered arginine-citrulline-ornithine pathways, revealing a previously unrecognized metabolic role of ANP in the NO/urea cycle. In the urine, ANP KO animals exhibited oxidative stress signatures (glutathione disulfide, ophthalmate, sulfolactate) and dysregulated nucleotide degradation products (p< 0.001) (dAMP; dCMP, dUMP, IMP), glycolytic and PPP intermediates, and osmolytes (myo-inositol). These findings identify novel urinary biomarkers of ANP deficiency and may indicate increased tubular metabolic strain. Microbial-derived indoles and phenolics were also elevated, suggesting a previously unrecognized gut-kidney metabolic axis regulated by ANP. In the heart, ANP KO animals showed increased purine degradation (p< 0.01) (hypoxanthine, xanthine), downregulated ADP (FC=-1.6), and UDP-GlcNAc (FC=-2.0) and UDP-glucose (FC=-1.5), identifying a novel cardiac hexosamine and purine turnover phenotype linked to metabolic remodeling. Conclusion: This study provides the first multi-organ metabolic map of ANP KO and reveals new ANP-regulated pathways, including dysregulation in hexosamine, methylation, purine, oxidative stress, and arginine/NO metabolism. These findings expand the physiological scope of ANP beyond natriuresis and blood pressure regulation, and may reveal fundamental metabolic mechanisms that result in predisposition to salt-sensitive hypertension and cardiorenal injury. Funding: AHA 25SFRNPCKMS1467444; NIH R01 HL148114 This abstract was presented at the American Physiology Summit 2026 and is only available in HTML format. There is no downloadable file or PDF version. The Physiology editorial board was not involved in the peer review process.