Evaluation of Blood Flow in the Submandibular Gland of the Dog by Fractional Uptake of Ionic and Particle Tracers 1

Summary

This study examined the fractional uptake of ¹⁶⁹Yb-labeled microspheres (about 25 μ in diam) and an ionic tracer (⁴²K or ⁸⁶Rb) by the same unstimulated submandibular gland as an index of its blood flow (total and/or functional). Cardiac outputs were measured to calculate a “blood flow” from these uptakes. To examine any changes in the uptake of the ⁴²K or ⁸⁶Rb with time, tissues were sampled 40-60 or 120-180 sec after injecting the ionic tracer for uptake of the ionic and particle tracers. For the 40-60-sec group of dogs, fractional uptake of the ionic tracer appeared to be similar to that of the microspheres. In the other group, uptake of the ionic tracer was significantly larger than that for the labeled microspheres. Injection of two differently labeled spheres (¹⁶⁹Yb and ⁸⁵Sr) sequentially demonstrated that uptakes of the spheres injected secondly were not different from those injected initially. Fractional uptakes of each type of sphere per unit weight were similar in the right and left gland, further supporting the particle distribution method as an approach for assessing blood flow to the salivary gland in experimental animals.