AJP - Endocrinology and Metabolism, Vol 246, Issue 4 369-E379, Copyright © 1984 by American Physiological Society
Hepatic extraction of exogenous insulin in depancreatized conscious dogs
T. Ishida, Z. Chap, J. Chou, R. M. Lewis, C. J. Hartley, M. L. Entman and J. B. Field
Hepatic and mesenteric extraction of exogenous insulin and glucose
appearance and clearance were compared in conscious depancreatized and
normal dogs after intraportal or peripheral intravenous insulin infusion.
Portal vein insulin levels were higher, whereas arterial insulin levels
were lower after intraportal compared with intravenous peripheral infusion
of insulin. During the intraportal infusion of 1 and 2 mU X kg-1 X min-1
insulin, 40 +/- 3% of the insulin presented to the liver was extracted by
that organ in the diabetic dogs, similar to the value obtained in normal
dogs (39 +/- 5%). Hepatic extraction of insulin after intravenous
peripheral infusion of that hormone was similar in normal and diabetic dogs
and was not significantly different from intraportal infusion. Mesenteric
extraction of insulin in the diabetic dogs (13 +/- 2%) was similar to the
19 +/- 3% in the normal animals. The blood sugar changes were similar after
both routes of insulin infusion. Suppression of glucose appearance in
diabetic dogs was also similar during both routes of infusion. Glucose
clearance during the peripheral intravenous infusion of insulin in diabetic
dogs was greater than during intraportal insulin. These findings indicate
that hepatic extraction of exogenous insulin was similar in normal and
depancreatized dogs and was not influenced by the different infusion
routes. Suppression of glucose appearance in diabetic dogs was similar
after both routes despite different portal vein insulin levels. The
peripheral action of intravenous peripheral infused insulin in diabetic
dogs was greater than that of intraportal insulin reflecting the higher
arterial insulin levels.
