Opposite effects of NAM and Melatonin
This paper suggests that Nicotinamide increases oxidative stress, but also increases expression of SAHH (AHCY), while melatonin does the opposite - reduces the expression of SAHH.
- Results showed that NAM (20 mM) administration during in vitro maturation (IVM) significantly reduced oocyte maturation and actin distribution, while induced reactive oxygen species (ROS) accumulation and mitochondrial dysfunction
- Inspecting the underlying mechanisms behind NAM-associated toxicity revealed an increase in transcription pattern of NAM methylation (NNMT and AHCY) genes in NAM-treated oocytes while the opposite profile was observed upon melatonin supplementation (R1)
This could be related to negative symptoms that some people experience from Melatonin (nightmares, psychosis) - if poorly functioning AHCY (SAHH) gets inhibited even more leading to increased SAH and lowered cysteine synthesis.
NAM apparently has dose dependent effect: small doses have positive effect, while high doses lead to negative effects. Another paper:
Our results showed that low NAM concentrations reduced the oxidative stress and improved mitochondrial profile, total cleavage and 8-16 cell stage embryo development whereas the opposite profile was observed upon exposure to high NAM concentrations (10 mM onward) (R2)