Estimation of renal tubular secretion in man, in health and disease, using endogenous N-1-methylnicotinamide

Nephron. 1992;60(1):12-6. doi: 10.1159/000186698.


We have been investigating the possibility of using the renal clearance of endogenous N-1-methylnicotinamide (NMN) as a marker of renal tubular function. Sixty-three subjects (11 healthy volunteers and 52 patients with renal impairment) were used for this study. The subjects were divided into three groups according to their creatinine clearance: group 1, over 80 ml/min; group 2, between 30 and 80 ml/min, and group 3, less than 30 ml/min. The correlation between NMN and creatinine clearance was compared for each group. A good correlation (r = 0.84) was found for groups 1 and 3 (r = 0.76), whereas for group 2, a poor correlation was found (r = 0.43). For subjects with mild renal impairment (group 2), there was clear evidence of glomerulo-tubular imbalance manifest by a larger variability in NMN clearance than creatinine clearance and an essentially non-parallel decline in these two parameters for this group. When all subjects were grouped together, the relationship between the clearance of NMN and of creatinine was best described by a 3-term polynomial equation (r = 0.93). NMN clearance is a potentially useful non-invasive marker of renal tubular function in man and provides additional information to that provided by the measurement of creatinine clearance alone. This substance should be more fully evaluated as a potential diagnostic aid.

MeSH terms

  • Adult
  • Aged
  • Aged, 80 and over
  • Biomarkers / blood
  • Biomarkers / urine
  • Creatine / blood
  • Creatine / urine
  • Female
  • Glomerular Filtration Rate / physiology
  • Humans
  • Kidney Diseases / blood*
  • Kidney Diseases / diagnosis
  • Kidney Diseases / urine*
  • Kidney Tubules / metabolism*
  • Kidney Tubules / physiology
  • Male
  • Middle Aged
  • Niacinamide / analogs & derivatives*
  • Niacinamide / blood
  • Niacinamide / urine


  • Biomarkers
  • Niacinamide
  • Creatine
  • N(1)-methylnicotinamide