The purification and properties of a thyroid-stimulating factor isolated from Clostridium perfringens.

Cultures of Clostridium perfringens produce a factor that stimulates the thyroid. The stimulating factor has been purified 300-fold by fractionation of the growth medium with ammonium sulfate, filtration on Sephadex G-100, and chromatography on diethylaminoethyl cellulose. The purified factor contains no proteolytic activity, and has been separated from neuraminidase and lecithinase C. When incubated with thyroid slices the purified factor, like thyroidstimulating hormone stimulates glucose-lJ4C oxidation, phospholipid synthesis, and the formation of intracellular colloid droplets. When injected into chicks, the factor causes the depletion of radioiodine. The factor is thought to be a protein since its activity is destroyed by treatment with Pronase. Its behavior on Sephadex G-100 suggests a molecular weight of about 30,000.