Separation of Long-Acting Thyroid Stimulator in Serum from Hyperthyroid Patient

Abstract

Attempts to extract a long-acting thyroid stimulator (LATS) in the serum from hyperthyroid patient, or at least to concentrate the activity of it, were performed by DEAE cellulose column chromatography.
5 ml of serum containing LATS was placed on a 2 * 30 cm. column pached with DEAE cellulose which was equilibrated at pH 8.4 with 0.005 M Tris buffer. The elution was carried out by the step-wise method as shown in Fig. 1. Fractions of 6 ml. were collected at the rate of 30 ml per an hour.
The activity of LATS was assayed by the Noguchi modification of McKenzie's method. The concentration of serum protein in each fraction was determined by Greenberg's method, and the paper electrophoresis was performed by the method which was reported by Mori et al.
Fig. 1 shows a typical chromatogram of the LATS under these conditions. Four fractions were separated. A LATS was found in the first fraction, which contained about 34% (mean value) by weight of the original serum protein (Table 2). The most of thyrotropin was in the second fraction (Table 1). From this result, it is concluded that thyrotropin differed from LATS on the adsorption for DEAE cellulose. On the development of paper electrophpresis, it was observed that the greater part of protein in the first fraction was γ-gliblin.
The clear separation of LATS from thyrotropin was not performed satisfactorily. However, it can be said, this method is useful to concentrate the activity of LATS in hyperthyroid serum.