tion from human bronchial epithelial cells grown in murine

10.1152/ajplung.00410.2002.—Studies of regulated mucin secretion from goblet cells in primary cultures of human bronchial epithelial (HBE) cells have suffered, generally, from poor signal-to-noise ratios, with reported secretory re-sponses of 100 % (less than onefold) relative to baseline. Using, instead, HBE cells grown as xenografts in the backs of nude mice, we found that UTP (100 M) stimulated strong mucin secretory responses from isolated, luminally perfused preparations. The peak response (10 min) for 11 control experiments (37 xenografts) was 3.3 0.05-fold relative to baseline, and the time-integrated response (60 min) was 23.4 0.5-fold. Because responses to ATP and UTP were approximately equal, an apical membrane P2Y2-receptor (R) is suggested. Additionally, ADP activated mucin release from HBE xenografts, whereas UDP and 2-methlythio-ADP di