Slominska Ewa M, Rutkowski Przemyslaw, Smolenski Ryszard T, Szutowicz Andrzej, Rutkowski Boleslaw, Swierczynski Julian
Department of Biochemistry, Medical University of Gdansk, Gdańsk, Poland.
Mol Cell Biochem. 2004 Dec;267(1-2):25-30. doi: 10.1023/b:mcbi.0000049359.66669.29.
N-Methyl-2-pyridone-5-carboxamide (2PY) is a major catabolite of NAD, which is excreted in the urine. Assay of plasma concentration and urine exrection of 2PY is of interest for monitoring niacin nutritional state and NAD catabolism. Aging has major impact on number of metabolic processes, but its effect on plasma and tissue 2PY concentration has not been studied so far. The present study was undertaken to investigate the effect of aging on human plasma 2PY concentration. Blood samples were collected from 78 (56 females and 22 males) healthy subjects at different age ranging from 5 to 90 years. Plasma ultrafiltrates were analyzed with liquid chromatography/mass spectrometry (LC/MS) for 2PY concentration. 2PY concentration was also evaluated in plasma and liver of young (2 month) and old (24 month) rats. The mean plasma 2PY concentration in young (5-16 years old) healthy subjects was 0.39 +/- 0.22 micromol/l while in old healthy subjects (50-90 years old) it was approximately 2.6-fold higher. No gender differences was found in plasma 2PY concentration. Univariate regression analysis displayed positive correlation between age and human plasma 2PY concentration (r = 0.57, p < 0.01) and between age and 2PY/creatinine ratio (r = 0.4, p < 0.01). Multivariate regression analysis indicates that both age and plasma creatinine concentrations were independently correlated with the increase in plasma 2PY concentration. Daily 2PY excretion with urine corrected for weight was approximately 30% lower in old subjects than in young humans. 2PY concentrations in liver and plasma of 2-month-old rats were lower than in 24-month-old rats. In conclusion, our results demonstrated that human plasma 2PY concentration increases with age. This could be a consequence of both decreased renal excretion and increased production in the the liver or other organs. Our results indicate that age should be taken into consideration in the interpretation of plasma 2PY concentration.
N-甲基-2-吡啶酮-5-甲酰胺(2PY)是烟酰胺腺嘌呤二核苷酸(NAD)的主要分解代谢产物,经尿液排出。检测血浆中2PY的浓度以及尿液中2PY的排泄量,对于监测烟酸营养状况和NAD分解代谢具有重要意义。衰老对众多代谢过程有重大影响,但迄今为止,衰老对血浆和组织中2PY浓度的影响尚未得到研究。本研究旨在探讨衰老对人体血浆2PY浓度的影响。从78名(56名女性和22名男性)年龄在5至90岁之间的健康受试者采集血样。采用液相色谱/质谱联用(LC/MS)分析法检测血浆超滤液中2PY的浓度。同时,还评估了年轻(2个月)和老年(24个月)大鼠血浆和肝脏中2PY的浓度。年轻(5至16岁)健康受试者血浆中2PY的平均浓度为0.39±0.22微摩尔/升,而老年健康受试者(50至90岁)的该浓度约高出2.6倍。未发现血浆2PY浓度存在性别差异。单因素回归分析显示,年龄与人体血浆2PY浓度之间呈正相关(r = 0.57,p < 0.01),年龄与2PY/肌酐比值之间也呈正相关(r = 0.4,p < 0.01)。多因素回归分析表明,年龄和血浆肌酐浓度均与血浆2PY浓度的升高独立相关。校正体重后,老年受试者每日尿液中2PY的排泄量比年轻受试者低约30%。2个月龄大鼠肝脏和血浆中的2PY浓度低于24个月龄大鼠。总之,我们的研究结果表明,人体血浆2PY浓度随年龄增长而升高。这可能是肾脏排泄减少以及肝脏或其他器官生成增加共同作用的结果。我们的研究结果表明,在解读血浆2PY浓度时应考虑年龄因素。