Is the effect of diphenolic laxatives mediated via release of prostaglandin E?

The diphenolic laxatives, bisacodyl and phenolphthalein, and the osmotic laxative mannitol increase intestinal fluid volume in the rat colon in situ. The diphenolic laxatives stimulate the biosynthesis of prostaglandin E (PGE) whereas mannitol does not. Inhibition of PG-biosynthesis by pretreatment with indomethacin only reduces the effect of the diphenolic laxatives. It is suggested that diphenolic laxatives increase intestinal fluid volume via stimulation of PGE biosynthesis in the colon.