β-Nicotinamide Mononucleotide, an Anti-Aging Candidate Compound, Is Retained in the Body for Longer than Nicotinamide in Rats

The turnover of the oxidized form of nicotinamide adenine dinucleotide (NAD 1 ) has attracted interest in regard to longevity. Thus, compounds that can rapidly increase the cellular NAD 1 concentration have been surveyed by many researchers. Of those, b-nicotinamide mononucleotide (b-NMN) has been focused on. Studies on the biosynthesis of NAD 1 from b-NMN have been reported at the cellular level, but not at the whole animal level. In the present study, we investigated whether b-NMN is superior to nicotinamide (Nam) as a precursor of NAD 1 in whole animal experiments. To this end we compared the NAD 1 concentration in the blood and the urinary excretion amounts of NAD 1 catabolites. Rats were intraperitoneally injected with b-NMN or Nam. After the injection, blood samples and urine samples were collected at 3-h intervals. The concentration of blood total NAD (NAD 1 1NADH) in each sample showed no significant differences between the two groups. The urinary excretion amounts of NAD 1 catabolites in the urine samples collected at 3-6 h after the injection were lower in the b-NMN group than in the Nam group. These results suggest that b-NMN is retained in the body for longer than Nam.