Urinary arginine and ornithine in occupational exposure to 2-ethylhexanoic acid

Nine sawmill workers were divided into two groups according to their exposure to 2-ethylhexanoic acid, (EHA), a pesticide which has replaced the older pentochlorophenol. The men with lower exposure excreted 30 +/- 10 nmol EHA/mmol creatinine (mean +/- SD, n = 4) in urine samples taken after the workshift, whereas men with higher exposure excreted 1.8 +/- 1.6 mumol EHA/mmol creatinine (mean +/- SD, n = 5, p less than 0.01). The urinary ornithine and arginine concentrations were at the lower exposure 1.4 +/- 0.4 and 1.5 +/- 0.8 mumol/mmol creatinine, respectively (mean +/- SD, n = 4), and they increased significantly (p less than 0.01) to 4.5 +/- 2.5 and 3.2 +/- 1.5 mumol/mmol (mean +/- SD, n = 5), respectively, at the higher exposure. This might have been caused by the inhibitory effect of EHA on urea synthesis which was partially compensated for by elevated arginine and ornithine concentrations to drive the urea cycle more efficiently.