In vitro gamma irradiation of some purified polypeptide hormones and their biological and radioimmunological activity
Hromadová, M.; Macho, L.; Strbák, V.; Vigas, M.; Mikulaj, L.
Endocrinologia Experimentalis 13(2): 115-122
1979
ISSN/ISBN: 0013-7200 PMID: 230958 Document Number: 141103
Some polypeptide hormones (ACTH, human and bovine growth hormone [GH], human menopausal gonadotropin [HMG], human luteinizing hormone [LH], and bovine thyrotropin [TSH]) were irradiated either with 2.5 or 12.5 Mrad (1.1 Mrad h-1) or both and their biological activity or immunoreactivity was tested within a few days or 3-5 mo. after irradiation. Biological activity of irradiated ACTH (estimation of corticosterone released into medium by incubated adrenals, Saffran and Schally, 1955) was not decreased in both time intervals tested. At 10 days after irradiation of bovine GH no changes in biological activity (tibia test, Wilhelmi, 1973) were found. Similarly, no decrease of biological activity of irradiated HMG (augmentation of ovarian and uterine weight, Butt 1973) was found 4 mo. after irradiation and, finally, no decrease of bovine TSH activity (radioiodine release from prelabeled thyroid in mice, McKenzie, 1958) was found 2-30 days after irradiation with 2.5 Mrad, while a decrease was observed after 12.5 Mrad. At 3-5 mo. after irradiation, however, there was a decrease in biological activity after both doses. The immunological reactivity of irradiated HMG and LH did not differ from that of unirradiated samples. The same was found with human GH after 2.5 Mrad, while a decrease of reactivity after 12.5 Mrad was detected. In most of the cases, the sterilizing dose of .gamma.-irradiation (2.5 Mrad) did not affect the biological activity of polypeptide hormones and the sensitivity of these to irradiation appears to be different.