The Assay of Thyroid Preparations Based on Increased Sensitivity to Adrenaline.: Studies on a New Method

Summary. The purpose of the studies was to test the accuracy of a new method of standardization based on the increased sensitivity to adrenaline of mice which is occasioned by thyroid powders. Three different thyroid preparations with practically identical total iodine content, were used. The biological efficacy of the preparations was compared by several biological methods of standardization. The acetonitrile method according to Grab gave no consistent results. The Morch method, based on the measurement of output of carbon dioxide, and the method to be tested, which rests on increased sensitivity to adrenaline, brought, out, differences in biological efficacy which are in agreement with results obtained in clinical studies. In the results obtained by the method based on increased sensitivity to oxygen deficiency the differences mentioned above are not visible. In clinical studies, the amount of serum protein bound iodine is found to follow sensitively other variations that occur in the clinical picture when different, preparations are used. The reaction must therefore be corisidered a good exponent, of the efficacy of the thyroid preparation. It is a serviceable medium for checking the results of standardization obtained in animal experinments on human patients suffering from hypothyreosis. The standardization method described in the present paper. delveloped on the basis of increase in sensitivity to adrenaline caused by thyroid powder, must he considered biologically specific, and the results obtained by it agree with clinical results. Technically the method is very simple and the possibility of errors is small.