Measurement of carbonic anhydrase isozyme VI (CA‐VI) in swine sera,colostrums, saliva,bile, seminal plasma and tissues

Swine secretory carbonic anhydrase VI (CA‐VI) was purified from swine saliva and an antibody to CA‐VI was generated. A specific and sensitive enzyme‐linked immunosorbent assay (ELISA) has been developed for the measurement of swine CA‐VI. The assay can detect as little as 5 ng/mL of swine CA‐VI. Typical standard curves were determined for a range of CA‐VI solutions (7.8 to 500 ng/mL). The coefficients of variation for these solutions were less than 5%. When 500, 250 or 100 ng/mL of swine CA‐VI was added to swine sera, the recoveries were 102.0%, 109.7% and 100.2%, respectively. The concentrations of CA‐VI in the saliva (26.2 ± 30.4 µg/mL), sera (3.3 ± 4.9 ng/mL), bile (153.0 ± 114.0 ng/mL), seminal plasma (124.0 ± 39.0 ng/mL) and parotid gland (441.3 ± 90.0 µg/g wet tissue), submaxillary gland (88.1 ± 124.4 µg/g wet tissue), sublingual gland (58.6 ± 24.6 µg/g wet tissue) and gallbladder (2.4 ± 1.3 µg/1g wet tissue) were determined by ELISA. The concentration of CA‐VI in colostrum was 163.3 ± 101.4 ng/mL and did not decrease within 10 days following parturition. An immunohistochemical reaction to anti‐CA‐VI antiserum was observed in the columnar epithelial cells lining the gallbladder. These data suggest that secretory CA‐VI plays various roles in pH regulation and the maintenance of ion and fluid balance.