Comparison of the circulation between fed and fasted normal and portal hypertensive rats.

The radioactive microsphere technique with the reference sample method was used for simultaneous determinations of splanchnic organ blood flow and cardiac output in fed and fasted anesthetized control rats and in rats with portal hypertension due to portal vein stenosis. Portal tributary blood flow was significantly higher in control (27.35 +/- 1.82 versus 14.60 +/- 0.96 ml/min) and in portal hypertensive (25.45 +/- 0.71 versus 20.09 +/- 1.27 ml/min) fed animals than in fasted rats, respectively. This difference was due to an increase in most of the splanchnic organ blood flows expressed in terms of either milliliter per minute or milliliter per minute per gram of tissue. The distribution of the cardiac output to the portal venous territory was also increased in fed animals as compared to fasted rats. In contrast, hepatic arterial blood flow was lower in fed animals than in fasted rats in both groups. Cardiac output was also significantly elevated in fed animals. This study demonstrates that the baseline circulatory state that depends on the digestive condition of these rats must be considered for splanchnic hemodynamic studies.