AJP - Gastrointestinal and Liver Physiology, Vol 250, Issue 3 316-G322, Copyright © 1986 by American Physiological Society
Pancreatic tissue oxygenation during secretory stimulation
S. L. Harper, V. H. Pitts, D. N. Granger and P. R. Kvietys
Pancreatic acinar tissue O2 tension (PO2) was measured in anesthetized rats
using recessed-tip microelectrodes (tip diam 1-2 micron). Pancreatic blood
flow was measured using radioactive microspheres. Volume rate of pancreatic
secretion, as well as protein concentration, was also measured. Average
resting PO2 was 24.8 +/- 1.6 mmHg, with relatively little variation evident
within a given pancreas. Bolus intravenous infusion of cholecystokinin
octapeptide (CCK-OP, 4 micrograms X kg body wt-1) induced a reduction in
tissue PO2 and profoundly increased protein output, while not directly
affecting pancreatic blood flow. By contrast, secretin infusion (1.0 CU X
kg body wt-1 iv bolus) affected neither tissue PO2 nor blood flow, although
secretory rate increased by nearly sevenfold. This difference in PO2
response to the two compounds is interpreted in light of the fact that
CCK-OP primarily stimulates acinar cell function, while secretin
preferentially activates secretory epithelium. Pancreatic PO2 was found to
be linearly related to resting blood flow at flows above 44 ml X min-1 X
100 g-1. No regional differences in blood flow were found in the head,
body, and tail of the pancreas.
