Abstract
Peripheral and portal plasma insulin concentrations were determined in eviscerated
cats before, during and after vagal stimulation. Basal peripheral insulin levels averaged
2.4 ng/ ml and portal levels 18 ng/ml.
The portal blood flow was recorded continuously, thus enabling the insulin output/min
to be calculated. In addition, the total insulin content of the pancreas was determined,
which permitted quantitative comparisons of insulin release and pancreatic insulin
content to be made. About 2% of the insulin store was released during one hour under
basal conditions.
Unilateral vagal stimulation with frequencies ranging between 1 and 20 Hz induced
an almost immediate release of insulin into the portal vein. Following stimulation
with frequencies of 3-4 Hz, the release mechanism was fatigued by a total of 2000-3000
impulses. The insulin output produced by such a supramaximal stimulation averaged
1.5 ug and constituted about 2% of the total pancreatic insulin content. 15-20 min
was needed for the release mechanism to recover.
Key words
Insulin Release - Vagal Stimulation - Cat
