Pharmacokinetics of ethylene in man; body burden with ethylene oxide and hydroxyethylation of hemoglobin due to endogenous and environmental ethylene

Abstract

The inhalation pharmacokinetics and the endogenous production of ethylene has been determined in healthy volunteers with respect to the formation of the carcinogen ethylene oxide. Ethylene showed a low degree of accumulation in the body determined in six subjects, the thermodynamic partition coefficient "body/air" being 0.53 +/- 0.23 (mean +/- SD) and the accumulation factor "body/air" at steady-state being 0.33 +/- 0.13 (mean +/- SD). The rate of metabolism was directly proportional to the exposure concentration. Only 2% of ethylene inhaled was metabolized to ethylene oxide, whereas 98% of ethylene was exhaled unchanged. The rate of the endogenous production of ethylene was 32 +/- 12 nmol/h (mean +/- SD), as calculated from exhalation data from 14 subjects. The resulting body burden was 0.44 +/- 0.19 nmol/kg (mean +/- SD). By analyzing published data on ethylene oxide in man its half-life was estimated to be 42 min. Using the pharmacokinetic parameters of ethylene and ethylene oxide, the body burden of ethylene oxide due to the sum of the exposure to environmental ethylene of about 15 ppb and to endogenous ethylene exposure of 0.44 nmol/kg was predicted to be 0.25 nmol/kg. In the blood of five non-smokers and one smoker the hemoglobin adduct resulting from the reaction of ethylene oxide with the N-terminal valine, N-(2-hydroxyethyl)valine, was quantified by gas chromatography/mass spectrometry. The value of 20 +/- 5 pmol/g Hb (mean +/- SD) found in the non-smokers corroborated the steady-state level of 18 +/- 3 pmol/g Hb (mean +/- SD) calculated from the pharmacokinetic approach.

On-line laser photoacoustic detection of ethene in exhaled air as biomarker of ultraviolet radiation damage of the human skin

“…During UV irradiation ethene exhalation does not reach a plateau, caused by the buffer capacity of the body tissue. 19 This is also shown in the twophase decay in ethene emission after exposure ͑Fig. 3͒; a fast decay results from wash out by the lungs and blood and a slow long-term decay from the body tissue.…”

Human inhalation exposure to ethylene glycol

“…A relevant EG source could be ethylene and ethylene oxide uptake via smoking (e.g. To¨rnqvist et al 1986;Filser et al 1992). A series of further possible sources for background EG, including food and consumer products, are discussed in IPCS (2002).…”

Methyl vinyl ketone—Identification and quantification of adducts to N-terminal valine in human hemoglobin

“…One such example is the adduct formed from ethylene oxide [2,3], which was shown to mainly originate from endogenously formed ethylene/ethylene oxide [4]. Another example is the N-(2-carbamoylethyl)valine adduct, which was proven to originate from acrylamide, shown to be formed in food during cooking [5,6].…”