Subcellular distribution of the pi effect in the pancreas of the guinea pig

Pancreas lobules incubated in vitro actively incorporate (2-³H) myotnositol into the PI associated with a number of different membranes, i.e., those of the rough- and smooth-surfaced microsomes, mitochondria, zymogen granules, as well as the plasmalemma. Stimulation of secretion with Acetylcholine + Eserine results in an increase of the incorporation (PI effect). This increase is approximately of the same order of magnitude (∼ 4fold) in all the Fractions. The results might be due either to a generalized breakdown of the PI associated with all the membranes under study, Followed by resynthesis, or to a rapid intracellular redistribution of the PI molecules, synthetized in response to the stimulation.