Recovery of liver function in two-third partial hepatectomized rats evaluated by L-[1-13C]phenylalanine breath test.
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.
Ishii
Yukimoto
Y
Departments of Pharmacology and Third Department of Surgery, Nihon University School of Medicine, Itabashi-ku, Tokyo, Japan.
Asai
Satoshi
S
Kohno
Tadashi
T
Ito
Asuka
A
Iwai
Shigetomi
S
Ishikawa
Koichi
K
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
D002247:Carbon Isotopes; D011506:Proteins; D010649:Phenylalanine; D004247:DNA; D010651:Phenylalanine Hydroxylase