Pseudomonas aeruginosa colonizes the lower respiratory tracts of patients with severe bronchiectasis, including cystic fibrosis, a condition associated with increased airway mucus output. We have shown that an extract containing chloroform-soluble extracellular products of P. aeruginosa releases glycoconjugates into the cat trachea in vivo. This activity was not related to pyocyanin, a major component of the extract, but was associated with the rhamnolipids. Purified monorhamnolipid (100 micrograms/ml) released radiolabeled and periodic acid-Schiff (PAS)-reactive glycoconjugates (delta 3H = +490 +/- 70%, delta 35S = +170 +/- 40%, delta PAS = +8.6 +/- 1.7 micrograms/min; n = 6, P less than 0.02 for each). Dirhamnolipid (200 micrograms/ml) was also effective (delta 3H = +640 +/- 70%, delta 35S = +130 +/- 20%, delta PAS = +9.3 +/- 1.5 micrograms/min; n = 6, P less than 0.02 for each). Monorhamnolipid (100 micrograms/ml) also released 35S-labeled and PAS-reactive glycoconjugates from human bronchial tissue in vitro (delta 35S = +189 +/- 47%, delta PAS = +26.3 +/- 8.5 micrograms/min; n = 7, P less than 0.001 versus control tissues in which no stimulus was given). The cat tracheal glycoconjugates released by the rhamnolipids differed from those released by pilocarpine 50 microM, in having a higher 3H:35S ratio (P less than 0.001). After gel chromatography on a Sepharose CL-4B column, the void volume fractions of the glycoconjugates also had different profiles in a cesium chloride density gradient. Those released by rhamnolipid banded at 1.62 g/ml, while those released by pilocarpine banded mainly at 1.50 g/ml, with some of the higher density material also present.(ABSTRACT TRUNCATED AT 250 WORDS)