SENSITIVE ENZYME-IMMUNOASSAY FOR RAT MN SUPEROXIDE-DISMUTASE - TISSUE DISTRIBUTION AND DEVELOPMENTAL PROFILES IN THE RAT CENTRAL NERVOUS-TISSUE, LIVER, AND KIDNEY

Sensitive enzyme immunoassay for measurement of rat Mn superoxide dismutase (Mn SOD) was established by using purified antibodies against rat Mn SOD, which were raised in rabbits with Mn-SOD purified from rat liver. The assay system consisted of polystyrene balls with immobilized anti-Mn SOD F(ab')2 fragments and the same antibody Fab' fragments labeled with beta-D-galactosidase from Escherichia coli. The assay was highly sensitive, and the minimum detection limit was 1 pg of Mn-SOD/assay tube. The immunoreactive Mn-SOD was detectable in all rat tissues examined, and it was present at high levels in the adrenal, heart, kidney, brain, stomach, duodenum, slow twitch muscles, and liver. Concentrations of Mn SOD in the central nervous tissue, kidney and liver were low at birth. But they increased gradually, reaching the adult levels by 5 weeks of age. Immunoreactive Cu/Zn SOD determined in the same samples showed similar increases after birth in each organ. However, the concentrations of Cu/Zn SOD were much higher than those of Mn SOD. Mn SOD concentrations decreased slightly during aging in the liver and kidney, and the concentrations at 25 months of age were significantly low as compared with those at 3 months of age.