AJP - Gastrointestinal and Liver Physiology, Vol 244, Issue 6 689-G694, Copyright © 1983 by American Physiological Society
Intestinal absorption of glandular kallikrein in the rat
A. Overlack, A. G. Scicli and O. A. Carretero
We studied the possibility of intestinal absorption of glandular kallikrein
in unanesthetized rats after administration of 5 mg of active or
phenylmethylsulfonyl fluoride-inactivated pig pancreatic kallikrein (PPK).
Immunoreactive PPK was measured in plasma and urine by radioimmunoassay
using an antiserum to PPK that does not cross-react with rat glandular
kallikrein. In addition, we studied the effect of intestinally administered
active PPK on the intestinal blood flow distribution. Although
immunoreactive PPK could not be detected (less than 10 ng/ml) in plasma
after active PPK was administered, very small amounts were found in urine
(20-40 ng/3 h). In the urine most of the PPK was in active form because
over 75% could be bound to aprotinin-Sepharose. After inactive PPK was
administered, immunoreactive PPK was detectable in the plasma of all rats,
and urinary excretion was higher than after administration of active PPK.
Blood flow distribution to the small intestine as a percentage of cardiac
output was significantly greater 30 min after intestinal application of
active PPK (5 mg) than after administration of the vehicle alone (1 ml of
0.9% saline). These results suggest that active and inactive PPK is
absorbed from the gut in very small amounts. The finding of higher amounts
of immunoreactive PPK in plasma and urine after inactive PPK was
administered is probably due to the fact that the inactive form of the
enzyme is not bound by the plasma inhibitors. These small amounts of
kallikrein absorbed appear to have some effect on intestinal blood flow
distribution.
