BRADYKININ STIMULATION OF ELECTROGENIC ION-TRANSPORT IN EPITHELIAL LAYERS OF CULTURED HUMAN ENDOMETRIUM

Primary cultures of glandular endometrial epithelial cells grown on permeable supports formed monolayers with a high transepithelial electrical resistance [1096 +/- 83 OMEGA.cm2 (n=34)] and displayed electrogenic ion transport as demonstrated by an inward short circuit current (I(sc); 20 +/- 2 muA/cm2). Bradykinin, 10(-8)-10(-6)M, added to either the basolateral or apical solutions enhanced the inward I(sc). The concentration-response curves for bradykinin were bell-shaped in nature. The I(sc) response was more sensitive to apical addition of bradykinin and the maximum response was also greater with apical bradykinin. The increases in I(sc) were accompanied by two- to three-fold increases in transepithelial conductance. Apical addition of amiloride, 10(-4)M, reduced the unstimulated I(sc) by 80%. In the presence of amiloride, the response to both apical and basolateral bradykinin was reduced by > 50 % in 8 out of 18 layers, and the mean response was reduced by approximately 25%. The data are consistent with a physiological role for bradykinin in the control of the intrauterine electrolyte environment, mediated in part by enhanced Na+ absorption.