Fig. 3. Western blot analyses of aquaporins in nasal glands of untreated (fw) and osmotically stressed (sw) ducklings using AQP1- and AQP5-specific antibodies. (A) AQP1 western blot of membrane proteins from duck lung (dlu), duck nasal gland (dng) and mouse lung (mlu) with (+) or without (–) sample pretreatment with N-glycosidase F (N-G-F). Note the obvious difference in total AQP1 content in lung and nasal gland preparations and the appearance of bands at a molecular mass of 28 kDa in the nasal gland samples after deglycosylation (open arrowheads) which are absent in untreated nasal gland samples. (B) AQP5 western blot of membrane proteins from duck lung (dlu), duck nasal gland (dng) and mouse lung (mlu) with (+) or without (–) deglycosylation using N-glycosidase F (N-G-F). (C) Relative intensities of western blot signals in protein isolates from nasal glands of untreated (fw) and osmotically stressed (sw) ducklings obtained with AQP1-specific antibodies (means ± s.d., N=5, **P<0.01, ANOVA). (D) Relative intensities of western blot signals in protein isolates from nasal glands of untreated (fw) and osmotically stressed (sw) ducklings obtained with AQP5-specific antibodies (means ± s.d., N=5, ***P<0.001, ANOVA).