Release of prostaglandins E and F from rat uterine strips incubated in depolarizing and hyperpolarizing solutions

The purpose of this study was investigate the effect of depolarizing (high K+, procaine 5mM, high K+Ca2+ free) or hyperpolarizing (K+ free)solutions on the generation and release of prostaglandins (PGs) E and F from the rat uterus. The output of PGs in the bathing solution was measured by bioassay. Results are expressed as ng/g dry weight/min. Under basal conditions in Krebs Ringer Bicarbonate medium, the total output of PGs (E + F) was 12.8 ± 0.9, 20.5 ± 2.5 and 39.1 ± 4.3 ng/dw/ min at 0–60, 60–80, 80–100 min intervals respectively, the major proportion being PGF like material in all cases. When the strips were bathed in depolarizing solution the total output increased significantly PGE being the most augmented. However, when K+ free solution was used there was a marked reduction in prostaglandins release as compared with basal conditions or depolarizing media. These results can not be attributed to osmotic effect, muscular work or neurotransmitter release from nerve endings. A close relationship between the variations in membrane potential and prostaglandins release seems to indicate that both parameters might correlate well.