AJP - Endocrinology and Metabolism, Vol 245, Issue 4 401-E409, Copyright © 1983 by American Physiological Society
Absence of hepatic extraction of pancreatic polypeptide in conscious dogs
T. Ishida, M. C. Chou, J. Chou, R. M. Lewis, C. J. Hartley, M. Entman, J. R. Kimmel and J. B. Field
In 15 conscious dogs basal portal vein pancreatic polypeptide (PP) (306 +/-
8 pg/ml) exceeded both hepatic vein PP (255 +/- 8 pg/ml) and arterial PP
(244 +/- 9 pg/ml) and increased rapidly 10 min after oral glucose
administration. In contrast to oral glucose, intraportal glucose infusion
decreased PP levels from 45 min until the end of the infusion. Meat
ingestion rapidly and promptly increased PP. During the basal state,
hepatic extraction of total immunoreactive PP was 10 +/- 4%, not
significantly different from zero, of the 150 +/- 14 ng/min presented to
the liver. Fractional hepatic extraction of PP did not change after oral
glucose, meat ingestion, or intraportal glucose infusion. Chromatographic
analysis showed at least four different components of immunoreactive PP.
The first peak eluted with the void volume, the second peak between the
void volume and authentic PP, and the third peak coincided with authentic
PP. When present, the fourth peak eluted after authentic PP. More than half
of the immunoreactive PP in the basal state eluted with authentic PP,
whereas about one-third was found in the second peak. The marked
alterations in PP after meat, oral glucose, or intraportal glucose and
atropine reflected primarily changes in the third peak. The fractional
hepatic extraction of all the components was very similar.
