Abstract
Using 99mTc-EDTA as a non-absorbable volume marker, perfusion experiments on guinea pigs colon
revealed the secretagogue effect of 0.7 mM rhein solution (circulating water increase
x = + 2.8 ml/hour, SD 0.6 ml, N = 10). After omission of rhein, gallotannins in a
0.1% concentration effectively inclined the stimulated secretion, into absorption
(x =-2.0 ml/hour, SD 0.4 ml, N = 4). Catechin (0.1%) had no marked effect. If a perfusion
with tri-or pentagalloylglucose is preceding a rhein perfusion, the secretagogue effect
of rhein is antagonised, although no absorption was detected. Catechin showed no activity.
The addition of tri- or pentagalloylglucose to a rhein containing perfusate inclines
significantly the observed secretion.
