Carbonic anhydrase II is secreted from bovine parotid glands.
Besides carbonic anhydrase VI (CA-VI), CA-II is suggested to be a second secreted isoenzyme in ruminant saliva. Therefore, the aim of the present study was to investigate the expression of salivary CA-II in bovine parotid glands at the protein level. Moreover, we intended to identify the cells which secrete the enzyme into the saliva. Two commercially available CA-II specific antibodies were tested for use in immunohistochemistry on frozen sections of bovine parotid tissue. Intense positive staining for CA-II was found in luminal duct cells and for the first time also inside the duct lumen, clearly demonstrating the expression and secretion of salivary CA-II in bovine parotid glands. The presence of CA-II protein was verified for parotid tissue and whole saliva using immunoblot analysis. Both salivary CA-II and CA-VI are highly active in supplying the alimentary tract with bicarbonate. It is suggested that a decrease in the expression of either one of these enzymes might severely disturb digestion and/or increase susceptibility to acidosis in ruminants.
Mau
M
M
Institute of Animal Science, University of Bonn, Bonn, Germany. mmau@itw.uni-bonn.de
Kaiser
T M
TM
Südekum
K-H
KH
D000818:Animals; D015153:Blotting, Western; D024402:Carbonic Anhydrase II / Q000378:metabolism*; D002417:Cattle; D007150:Immunohistochemistry; D010306:Parotid Gland / Q000201:enzymology / Q000378:metabolism*; D012463:Saliva / Q000201:enzymology / Q000378:metabolism*
D024402:Carbonic Anhydrase II