Pancreatic blood flow and its relationship to pancreatic interstitial pressure were investigated in a model of chronic pancreatitis in cats using a hydrogen gas-clearance technique with an intraductal electrode. The intraductal technique correlated well with blood flow measurements made using gamma-labeled microspheres (r = 0.88, P less than 0.001). In control cats, the basal blood flow of 69.1 +/- 9.5 mL.min-1.100 g-1 increased by 25% to 86.2 +/- 11 mL.min-1.100 g-1 with secretory stimulation (P less than 0.05). Interstitial pressure was -0.02 +/- 0.3 mm Hg and did not change significantly with stimulation. In cats with chronic pancreatitis, basal interstitial pressure was 1.8 +/- 0.5 mm Hg and basal blood flow 39.9 +/- 4 mL.min-1.100 g-1 (P less than 0.05). Stimulation of the chronic pancreatitis gland increased the pressure to 3.0 +/- 0.4 mm Hg (P less than 0.01) and reduced flow 15% to 34.2 +/- 4 mL.min-1.100 g-1 (P less than 0.05). Papaverine increased blood flow in control and chronic pancreatitis cats without altering tissue pressure, suggesting that despite the reduced basal blood flow, the ability to increase blood flow was preserved in chronic pancreatitis. The increased interstitial pressure associated with secretion appeared to limit the gland's normal hyperemic response in this model of chronic pancreatitis.