Consideration of Diurnal Variations in Human Blood NAD and NADP Concentrations

Abstract

SummaryThe sum of the urinary excretion of nicotinamide and its catabolites, which are metabolites of NAD and NADP, were observed to have clear diurnal variations in human urine. Then, we examined whether NAD and NADP in blood also showed the diurnal variation. All subjects were housed in the same facility and given the same diet during the experiment. In addition, we examined whether diurnal variations were affected by the intakes of dietary nicotinamide or not. As a result, neither the NAD nor the NADP content of the blood shows the diurnal variation regardless of the administered amount of nicotinamide. The concentrations of NAD and NADP did not increase according to the intake of nicotinamide. The existence of a mechanism by which NAD and the NADP levels of the blood are constantly maintained by the adjustment of the amount of excretion to the urinary bladder, was suggested. Key Words diurnal variation, NAD, blood, human, vitaminWe reported a diurnal variation in the NAD and NADP catabolites N 1 -methylnicotinamide, N 1 -methyl-2-pyridone-5-carboxamide, and N 1 -methyl-4-pyridone-3-carboxamide was observed ( 1 ) and an elevation of blood NAD level after moderate exercise ( 2 ). In the present study, we examined whether NAD and NADP in blood also showed the diurnal variation. In addition, we examined whether diurnal variations were affected by the intakes of dietary nicotinamide or not.Ten healthy male Japanese college students participated in the present experiment. They did not have regular use of medications or dietary supplements, or habitual alcohol or cigarette consumption. Their age, body weight, height and body mass index (mean Ϯ SD) were 22.1 Ϯ 2.3 y old, 63.6 Ϯ 5.2 kg, 174.0 Ϯ 4.6 cm, and 21.0 Ϯ 1.6 kg/m 2

Plasma B Vitamers: Population Epidemiology and Parent-Child Concordance in Children and Adults

“…Since the vitamin B2 group is involved in the KREBS cycle and fatty acid redox reactions for energy production [3,13], higher FMN levels in children with lower baseline riboflavin levels may reflect an improved efficiency of metabolic utilisation of riboflavin, with increased demands during the growth phase. FMN may be less affected by generational riboflavin fluctuations, consistent with homeostatic maintenance of metabolically active B vitamers that are key players in vital pathways of energy production and antioxidant mechanisms [7,31,32]. These hypotheses are further supported by previous findings [29,[31][32][33].…”

Control of Tissue-Resident Invariant NKT Cells by Vitamin A Metabolites and P2X7-Mediated Cell Death

“…The intestine has high levels of ATP, which is mainly produced from gut bacteria (45,46). Significant levels of NAD are present in body fluids including the blood plasma (47). Together with the high level of P2X7 expression by intestinal iNKT cells, this creates an effective environment to control iNKT cells.…”

Relationship between Urinary Concentrations of Nine Water-soluble Vitamins and their Vitamin Intakes in Japanese Adult Males

“…We have previously reported that urinary excretion of water-soluble vitamins closely reflects the excess water-soluble vitamins in rats 1–15 and humans. 16–27 Nutritional assessment using biomarkers is persuasive and leads to quick changes in dietary habits. We have not yet assessed whether there is a strong relationship between urinary excretion and vitamin intake in males.…”