Animal maturity influences prostaglandin effects on gallbladder fluid transport and smooth muscle

Prostaglandin (PG) A, E and F compounds applied serosally inhibited net fluid absorption and increased intraluminal pressure in guinea-pig isolated gallbladder. The inhibition was dose-dependent for a given animal body weight but sensitivity varied inversely with animal body weight; relative potencies were PGE2 greater than F2alpha greater than A1. In heavier animals the inhibition was preceded by an apparent increase in fluid absorption, due to fluid extrusion following muscle contraction. Net fluid secretion was observed at higher concentrations of PGE2 or F2alpha in lighter animals. Mucosally applied PGs less potently inhibited absorption, with relative potencies of PGE2 greater than A1 greater than F2beta greater than F2alpha. The spasmogenic effect was estimated by measuring intraluminal pressure (PGE2 greater than F2alpha greater than A1).