Metabolic influence on circadian oscillations рH and Eh in urine and saliva

Abstract

Urine and saliva are the most accessible liquids for studying circadian oscillations coherent with the activity of ongoing metabolic processes, which are characterized by a change in the rate and direction of the formation of protons (H+) and electrons (ē). The existing balance of acid-base state (pH) and redox potential (Eh) is an important indicator of homeostasis, reflecting the state of energy metabolism, i.e., the process of dissimilation. If the stability of the main (basic) metabolism does not change during the day, then the rate of facultative energy-consuming processes increases significantly during the daytime and decreases at night.Endogenous formation of hydrogen cations (H+) accompanies all transformation reactions of adenosine triphosphate. Thus, glycolysis is accompanied by lactic acidosis of the cytoplasm, and the tricarboxylic acid cycle performs a hydrogen-donor function, supplying protons (H+) to the respiratory chain of mitochondria. At the same time, depending on the rate of oxidative phosphorylation, a certain part of hydrogen cations (H+) is excreted into the intercellular space, from where it subsequently enters saliva and urine.Daily oscillations of pH and Eh in the urine and oral fluid (saliva) of healthy people reflect the circadian rhythm of metabolic processes and can be important indicators of metabolic disorders in common diseases accompanied by impaired energy metabolism.