Abstract
S-100 protein, a nervous system-specific protein, was determined in a soluble extract of various rat tissues with a sensitive enzyme immunoassay method, which consisted of a solid-phase with immobilized anti-S-100 antibody and the antibody labeled with β-D-galactosidase from Escherichia coli. The minimum detectable amount of S-100 protein was 3 pg/assay. Central nervous tissues (cerebrum, cerebellum, and brain stem) contained 1.4 to 2.8 μg S-100 protein/mg protein, whereas most of the peripheral tissues contained less than 0.05 μg/ml of the specific protein. However, the level of S-100 protein was high in adipose tissue (0.5-1.1 μg/mg) and in trachea (about 0.5 μg/mg), which involves cartilage. The S-100 protein levels in several tissues were significantly higher in female rats than in males at ages of 5 to 6 weeks.
