['Neonatal total parenteral nutrition (TPN) is associated with animals with low glucose tolerance, body weight, and physical activity at adulthood. The early life origin of adult metabolic perturbations suggests a reprogramming of metabolism following epigenetic modifications induced by a change in the pattern of DNA expression. We hypothesized that peroxides contaminating TPN inhibit the activity of DNA methyltransferase (DNMT), leading to a modified DNA methylation state.', "Three groups of 3-d-old guinea pigs with catheters in their jugular veins were compared: (i) control: enterally fed with regular chow; (ii) TPN: fed exclusively with TPN (dextrose, amino acids, lipids, multivitamins, contaminated with 350 ± 29 μmol/l peroxides); (iii) H2O2: control + 350 μmol/l H2O2 intravenously. After 4 d, infusions were stopped and animals enterally fed. Half the animals were killed immediately after treatments and half were killed 8 wk later (n = 4-6 per group) for hepatic determination of DNMT activities and of 5'-methyl-2'-deoxycytidine (5MedCyd) levels, a marker of DNA methylation.", 'At 1 wk, DNMT and 5MedCyd were lower in the TPN and H2O2 groups as compared with controls. At 9 wk, DNMT remained lower in the TPN group, whereas 5MedCyd was lower in the TPN and H2O2 groups.'] Does total parenteral nutrition induce sustained hypomethylation of DNA in newborn guinea pigs?