title: Reduction in carbonic anhydrase activity in the tongue epithelium and submandibular gland in zinc-deficient rats.
abstract: We investigated the effects of zinc deficiency on carbonic anhydrase (CA) activity in the tongue epithelium and submandibular gland in rats. Male 4-week-old SD rats were given free access to a diet containing 2.2 (zinc-deficient), 4.1 (low-zinc), or 33.7 (zinc-sufficient) mg zinc/kg diet for 6 weeks. Rats in the fourth group (receiving 33.7 mg zinc/kg) were pair-fed against the zinc-deficient rats. Biochemical analysis at the end of the experimental period indicated that zinc deficiency significantly reduced CA activity in the tongue epithelium and submandibular gland, and the CA activity levels in these tissues seemed to parallel the dietary zinc levels. By enzyme histochemistry, an intensely positive reaction for CA was observed in the middle and basal regions of the taste buds in the circumvallate papilla in the zinc-sufficient and pair-fed (control) rats. The cells in von Ebner's glands also showed a strong positive reaction in control rats, although only a weak reaction product was found in zinc-deficient rats. These results suggest that CA activity is affected by the dietary content of zinc, which is considered to be an indispensable factor for the maintenance of normal taste sensation.
authors.affiliation: Laboratory of Nutrition, Graduate School of Agricultural Science, Tohoku University, Sendai, Japan.
authors.forename: T
authors.initials: T
authors.lastname: Goto
authors.forename: M
authors.initials: M
authors.lastname: Komai
authors.forename: B P
authors.initials: BP
authors.lastname: Bryant
authors.forename: Y
authors.initials: Y
authors.lastname: Furukawa
mesh_terms: D000821:Animal Feed; D000818:Animals; D002256:Carbonic Anhydrases / Q000378:metabolism*; D004848:Epithelium / Q000201:enzymology; D005629:Frozen Sections; D006651:Histocytochemistry; D008297:Male; D051381:Rats; D017207:Rats, Sprague-Dawley; D013363:Submandibular Gland / Q000201:enzymology*; D013649:Taste; D014059:Tongue / Q000201:enzymology*; D015032:Zinc / Q000008:administration & dosage / Q000172:deficiency* / Q000494:pharmacology
chemical_list: D002256:Carbonic Anhydrases; D015032:Zinc