title: Recovery of liver function in two-third partial hepatectomized rats evaluated by L-[1-13C]phenylalanine breath test.
abstract: BACKGROUND
  We have previously reported that by means of a breath test with intravenously administered L-[1-13C] phenylalanine (13Cphe), hepatopathy could be quantitatively evaluated by measuring expiratory 13CO2 levels in a short period. It is known that phenylalanine hydroxylase activity (PAHA) plays an important role in phenylalanine metabolism. We examined the relationship between changes in PAHA and the results of the 13Cphe breath test during hepatic regeneration in a rat model of 70% hepatectomy, to assess their usefulness for evaluating hepatic regeneration.
  
  
  METHODS
  Male Wistar rats (Shizvoka Laboratory Animal Center, Hamamatsu, Japan) weighing 230 to 290 g were subjected to 70% hepatectomy under anesthesia with sodium pentobarbital. One, 2, 3, 5, 7, and 14 days postoperatively, 30 mg/kg 13Cphe was intravenously injected into the femoral vein, and the increase in exhaled 13CO2 (Delta 13CO2) was measured for 15 minutes. Simple laparotomy was performed in control rats. After the breath test, the regenerated liver was removed and weighed. The amount of DNA, amount of hepatic tissue total protein (TP), and PAHA were determined.
  
  
  RESULTS
  The r between liver weight/body weight and PAHA, between DNA and PAHA, and between TP and PAHA were 0.832, 0.720, and 0.758, respectively. Breath test graphs revealed that liver weight/body weight, DNA, and TP showed the best correlations with the peak value of Delta 13CO2 (liver weight/body weight percentage, r = 0.801; DNA, r = 0.660; TP, r = 0.706), and r between PAHA and peak value was 0.638.
  
  
  CONCLUSIONS
  These results suggest that measurement of PAHA in regenerated liver is an effective method for following up liver function after hepatic resection. Moreover, the 13Cphe breath test may also be useful to evaluate liver function after partial hepatectomy.
authors.affiliation: Departments of Pharmacology and Third Department of Surgery, Nihon University School of Medicine, Itabashi-ku, Tokyo, Japan.
authors.forename: Yukimoto
authors.initials: Y
authors.lastname: Ishii
authors.forename: Satoshi
authors.initials: S
authors.lastname: Asai
authors.forename: Tadashi
authors.initials: T
authors.lastname: Kohno
authors.forename: Asuka
authors.initials: A
authors.lastname: Ito
authors.forename: Shigetomi
authors.initials: S
authors.lastname: Iwai
authors.forename: Koichi
authors.initials: K
authors.lastname: Ishikawa
mesh_terms: D000818:Animals; D001835:Body Weight; D001944:Breath Tests; D002247:Carbon Isotopes; D004247:DNA / Q000378:metabolism; D006498:Hepatectomy / Q000379:methods*; D008099:Liver / Q000378:metabolism / Q000473:pathology / Q000503:physiopathology*; D008111:Liver Function Tests; D008115:Liver Regeneration / Q000502:physiology; D008297:Male; D009929:Organ Size; D010649:Phenylalanine; D010651:Phenylalanine Hydroxylase / Q000378:metabolism; D011506:Proteins / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D020127:Recovery of Function
chemical_list: D002247:Carbon Isotopes; D011506:Proteins; D010649:Phenylalanine; D004247:DNA; D010651:Phenylalanine Hydroxylase