Integrated Regulatory Model of Bile Acid Signaling, Renal Nitric Oxide Execution, and Hydration-Dependent Hyperchloremia, V 2.0, February 2026

Version 2.0 introduces a three-level regulatory execution framework linking upstream bile acid signaling, renal nitric oxide–mediated execution, and downstream hyperchloremic phenotype. In this model, hyperchloremia represents a downstream concentration marker of hydration and regulatory state rather than evidence of impaired structural kidney function. Bile acids act as endocrine signaling molecules through FXR and TGR5 receptor pathways, influencing vascular tone, metabolic regulation, autonomic signaling, and renal physiology. These upstream regulatory signals converge on renal nitric oxide availability, which governs afferent arteriolar tone, renin initiation, renal blood flow distribution, and tubular electrolyte handling. This nitric oxide–mediated execution layer determines how regulatory conditions are translated into physiological outcome. When renal execution shifts toward a conservation state, dehydration physiology may develop despite preserved filtration capacity. Relative chloride elevation emerges as a downstream concentration effect of altered hydration and acid–base distribution. Hyperchloremia therefore reflects regulatory execution state rather than intrinsic kidney failure. This framework provides mechanistic continuity linking metabolic signaling, renal vascular regulation, nitric oxide–mediated execution, hydration stability, and electrolyte phenotype. It offers a physiological explanation for hyperchloremia observed in structurally normal kidneys and generates testable predictions consistent with established renal physiology.