AJP - Gastrointestinal and Liver Physiology, Vol 243, Issue 4 268-G275, Copyright © 1982 by American Physiological Society
Effect of phenolphthalein on monkey intestinal water and electrolyte transport
D. W. Powell, P. T. Johnson, J. C. Bryson, R. C. Orlando and C. C. Fan
To assess Na-K-ATPase inhibiton and prostaglandin synthesis stimulation as
the mechanism of the secretory (cathartic) action of phenolphthalein in the
primate, we investigated water and electrolyte transport and Na-K-ATPase
levels in monkey intestine. Both jejunum and colon were studied with in
vivo perfusion and in vitro Ussing chamber techniques. Water, Na, and Cl
absorption was inhibited or secretion was induced by phenolphthalein
(10(-3) M) in the jejunum and colon when the drug was present in the
mucosal bathing (perfusion) solution. Serosal addition of phenolphthalein
(10(-4) or 10(-3) M) induced Na and anion absorption in the jejunum but not
in the colon. Phenolphthalein inhibited Na-K-ATPase activity in the test
tube, but assays of intestine previously perfused or bathed in the drug
showed no inhibiton. Indomethacin, in doses sufficient to inhibit
prostaglandin synthesis in the intestine, inhibited the secretion induced
by phenolphthalein in the jejunum but not in the colon. These
inconsistencies cast doubt on the role of Na-K-ATPase inhibition or the
role of prostaglandin synthesis stimulation in the mechanism of action of
phenolphthalein.
