Simultaneous measurement of metabolic flux in portally-drained viscera, liver, spleen, kidney and hindquarter in the conscious pig.

A method was developed to measure metabolic fluxes simultaneously across the portally-drained viscera (PDV), liver, spleen, kidney and hindquarter (HQ) in the conscious pig (20-25 kg). For this purpose, sampling catheters were implanted in the abdominal artery, portal vein, hepatic vein, splenic vein, renal vein and caval vein. Further, two extra infusion catheters were implanted in the splenic vein and abdominal artery. These allow continuous infusion of para-aminohippuric acid (PAH), providing a method for estimating the plasma flow of the liver, PDV, spleen, kidney and HQ. To minimize the postoperative recovery period of the pigs, great attention was paid to the housing conditions. After a recovery period of seven days, pigs were used for experiments twice a week. During the three weeks experimental period, food intake, body temperature, weight gain, blood gas data and plasma flow were monitored. Mean plasma flow was: liver 52 +/- 6, PDV 40 +/- 5, HQ 20 +/- 2, spleen 4 +/- 1 and kidneys 15 +/- 2 ml/kg body weight/min. These data were characteristic for a pig in a conscious normal resting and unstressed state. The long-term patency rate of the sampling catheters was very high (ranging from 75% to 100%). This was probably due to the prevention of catheter-related infections using a gentamicin (20 mg/ ml), alpha-chymotrypsin (225 U/ml) solution as catheter filling. We conclude that this model enables simultaneously liver, PDV, intestine, spleen, liver, kidney and HQ flux measurement of many metabolic substances in the conscious pig.