The Sources of Sodium in Rabbit Pancreatic Juice

Summary

Using an in vivo rabbit pancreas preparation, we have shown that approximately 85-90% of the sodium found in rabbit pancreatic juice comes directly from the circulating blood of the animal as opposed to fluids bathing the peritoneum. This conclusion is reached using data from radi-otracer experiments in which the blood and synthetic peritoneal fluid Na is labeled with ²²Na and ²⁴Na, respectively. The appearance of the various isotopes in the pancreatic juice has been used to determine the relative contributions of the two Na sources. The preference of the in vivo pancreas for vascular Na suggests that studies of pancreatic secretory mechanisms done in vitro may not be physiolgoically meaningful.

We would like to express our gratitude to Miss Deborah Hart for her devoted technical assistance. This work was supported in part by Research Grant 5 RO1-AM 17843-02 from the National Institute of Arthritis, Metabolism and Digestive Diseases.