5 × 1.5 m pens with ad libitum access to tap water from water nipples, liquid dietary supplement and digestive energy mixed with water. Light was supplied on a 12:12 hour schedule. Four pigs were subject to a 60% PHx (group one), four pigs were subject to sham surgery (group two) and four pigs were used as controls (group three). Control animals were necessary, as all of these animals were growing, and a measurement of normal liver growth was needed. All pigs were re-operated at three- and at six weeks post PHx. Biopsies were sampled upon initial laparotomy (t = 0), at three weeks post PHx (t = 1) and upon termination at six weeks post PHx (t = 2). This project was approved in agreement with the Norwegian Animal Welfare

Act § 21 and The Norwegian Regulation on Animal Experimentation §§ 7, 8 and 13. Our department is run in agreement with the European Convention for the Protection of Vertebrate Animals used GSI-IX for Experimental and Other Scientific Purposes. Anaesthesia The animals were fasted overnight with free access to water. They were initially sedated

with Ketamin (10 mg/kg intramuscularly (i.m.)) and Atropin (0.05 mg/kg i.m.). All animals were intubated, and anaesthesia was maintained with Isoflurane 1.5–2% mixed with 50–60% oxygen. Respiratory rate was adjusted to achieve an Et CO2 between 35 and 40 mmHg. Intravenous (i.v) access was obtained through a vein on the ear. Analgesia SN-38 was induced and maintained with Fentanyl 0.01 mg/kg, i.v. All animals received a peroperative i.v. volume load consisting of 1000 ml Ringer solution. Volume infusion was continued thereafter with 20 ml/kg/hr 0.9% NaCl and 10% Glucose. Before surgery, all animals

received a single intramuscular injection of antibiotic prophylaxis with Enrofloxacin 2.5 mg/kg. Monitoring The cardio-respiratory status was monitored with an electrocardiogram (ECG), invasive arterial blood pressure via a cannula in the femoral artery and by hourly arterial blood gas analysis. Intravascular pressure monitoring was performed using calibrated transducers connected to an amplifier (Gould, 3-oxoacyl-(acyl-carrier-protein) reductase 2800S, Ohio, USA). Portal venous pressure was monitored via a paediatric central venous catheter (CVK (Arrow International)) placed directly in the portal vein. Mean alveolar concentration of Isoflurane was monitored using a Capnomac (Nycomed Jean Mette). Body temperature was maintained at A-769662 datasheet approximately 39°C with a heating blanket. All recordings were documented hourly until extubation. The same anaesthesia protocol was employed for surgery at 3 and 6 weeks after PHx. Upon experiment termination, the pigs were sacrificed with an overdose of 100 mg Pentobarbital i.v. and 20 mmol KCl intracardially. The liver was removed and volume and wet weight was measured. Surgical procedures A midline laparotomy was used for access to the hepatic hilus. A reference biopsy was sampled from segment IV before resection (t = 0) and stored immediately in RNALater (Ambion).