Western blot confirmation of the H ⁺/K ⁺-ATPase proton pump in the human larynx and submandibular gland

Objective. The authors have previously demonstrated the H ⁺/ K ⁺-ATPase (proton pump) in human larynx and lung glands via immunohistochemistry (IHC). The present hypothesis is that the proton pump is expressed in other seromucinous glands of the digestive tract that can be confirmed by IHC and Western blot analysis. Study Design. Prospective controlled tissue analysis study. Setting. Academic medical institution. Methods. Ten anonymous fresh-frozen donor specimens were obtained, comprising 3 submandibular glands, 4 larynges, and 3 normal stomach specimens for control. Submandibular gland sections were immunostained with 2 monoclonal antibodies selectively reactive with α or β subunits of the H ⁺/K ⁺-ATPase. Western blot analysis was performed on all specimens. Results. Consistent IHC staining was observed in the submandibular gland specimens for both α and β subunits. Western blot analysis revealed very strong expression for the stomach at 100 kDa, corresponding to the α protein, and weak but notable banding for all larynx and submandibular gland specimens. Similar findings were noted for the 60- to 80-kDa glycosylated β subunit protein, as well as the 52-kDa β subunit precursor for all specimens. Conclusion. The H ⁺/K ⁺-ATPase (proton) pump is present in the human larynx and submandibular gland although in much lower concentrations than in the stomach. Proton pump involvement in human aerodigestive seromucinous glands may have a role in protecting mucosa from acid environments (local or systemic), explain heightened laryngeal sensitivity in those patients with laryngopharyngeal reflux, and be a site of action for proton pump inhibitor pharmacotherapy.