C2C12 cells were incubated for 48 hours with 30 mM sodium chlorate. Sulfate incorporation during the last 18 hours was measured in medium and detergent extracts. [35S]Sulfate radioactivity for total (proteoglycans plus glycosaminoglycans) and trichloroacetic acid-precipitated material (proteoglycans) samples, spotted on filters containing the cationic detergent cetyl pyridinium chloride ( CPC), was measured with liquid scintillation counting. DNA content was measured in same aliquots of detergent extracts (13.3 μg/μl for control and 18.0 μg/μl for chlorate treated cells). The specific activity values correspond to the means ± SD obtained from three different plates.