[Gram-negative bacteria influence on the ability of the arginine-vasotocin to stimulate osmotic permeability of the frog urinary bladder epithelium].

The influence of endogenous gram-negative bacteria colonizing the mucosal epithelium of frog Rana temporaria L. urinary bladders (FUB) on arginine-vasotocin AVT-stimulated osmotic water flow in isolated urinary bladders was investigated. 170 animals were examined and only 40% were contaminated with gram-negative bacteria (about 10(3)-10(6) CFU per hemibladder). Several Enterobacteriaceae species were identified (Hafnia alvei, 36.7%, E. coli, 32.3%, Serratia marcescens, 8.8%, Citrobacter freundii, 4.4% etc.). Basal osmotic water flow level was invariable in "clean" and contaminated FUB, whereas bacterial contamination resulted in considerable decrease in AVT-stimulated water flow ("clean": 2.53 +/- 0.13, n = 59, contaminated: 1.21 +/- 0.17 me/min/cm2, n = 38, p < 0.001, within first 15 min of incubation with 5 x 10(-10)M AVT). Gentamycin protection assay revealed predominantly adhesive forms of bacteria. Thus our data indicated that the presence of gram-negative bacteria colonizing the mucosal epithelium of the urinary bladder results in decreased adility of ADH to rise osmotic water permeability which in turn could impair body osmoregulation.