Biochemical and physiological aspects of 2,5-hexanedione: endogenous or exogenous product?
This article reports results regarding two different physiological aspects of 2,5-hexanedione (2,5-HD). The first is the relationship between "free" 2,5-HD (the fraction of "real" 2,5-HD) and "total" 2,5-HD (2,5-HD obtained from acid hydrolysis) in urine and blood of workers exposed to n-hexane. The second part of the study is an attempt to clarify "physiological" excretion of 2,5-HD in subjects not occupationally exposed to n-hexane. The concentration of free 2,5-HD in urine of workers exposed to n-hexane is about 8% of total urinary 2,5-HD. In blood, free 2,5-HD is about 50% of the total. The serum concentration range of total and free 2,5-HD in workers from whom blood was taken was 33-418 micrograms/l and 14-283 micrograms/l respectively. In subjects not exposed to n-hexane, urinary concentration of 2,5-HD ranged between 0.17 and 0.98 mg/l, the urinary excretion rate between 0.23 and 0.57 microgram/min, and renal clearance between 14 and 66 ml/min. The blood concentration of 2,5-HD in nonexposed subjects was 6-30 micrograms/l. Fluctuations typical of a circadian rhythm were not observed for 2,5-HD in blood or urine. We think that 2,5-HD is mainly a product of intermediate metabolism in the human body. Only a minimal part could derive from n-hexane as a ubiquitous micropollutant.
Perbellini
L
L
Institute of Occupational Medicine, Policlinico Borgo Roma, Verona, Italy.
Pezzoli
G
G
Brugnone
F
F
Canesi
M
M
D002940:Circadian Rhythm; D006586:Hexanes / Q000009:adverse effects*; D006588:Hexanones / Q000097:blood* / Q000652:urine*; D006801:Humans; D016273:Occupational Exposure / Q000009:adverse effects*; D012997:Solvents / Q000378:metabolism
D006586:Hexanes; D006588:Hexanones; D012997:Solvents; C026385:n-hexane; C011269:2,5-hexanedione