EFFECT OF GAMMA-IRRADIATION ON BIOLOGICAL-ACTIVITY OF THYROTROPIN

  • 1 January 1976
    • journal article
    • research article
    • Vol. 10  (1) , 3-11
Abstract
The biological activity of thyrotropin (TSH) was tested after sterilization by 0.5 and 12.5 Mrad of .gamma.-irradiation. The biological activity (McKenzie''s assay) of TSH irradiated in dry state was not affected during the 1st mo. after sterilization by doses of 0.5 and 2.5 Mrad. A substantial decrease of TSH biological activity was observed 3-5 mo. after the irradiation, the lower activity being after the former dose. The irradiation of TSH by 12.5 Mrad in dry state and by 0.5 and 2.5 Mrad in solution resulted in a decrease of biological activity already during 1st mo. The structural changes in the molecule of TSH were apparently not very extensive, since a decrease of disulfide bonds from 0.96-0.77 M/1 M of TSH was found immediately after the irradiation, while UV absorbancy and electrophoretic mobility on polyacrylamide gel electrophoresis were unaffected. These changes were followed by the decrease of TSH stability during storage in dry state. It is hypothesized that TSH molecule may be affected in .beta. subunit or in its connection with .alpha.

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