Ionizing radiation and somatostatin analogues are used for acromegaly treatment to achieve normalization or reduction of growth hormone hypersecretion and tumor shrinkage. In this study, we investigated a combination of somatostatin (SS14) with ionizing radiation of (60)Co and its effect on reparation of radiation-induced damage and cell death of somatomammotroph pituitary cells GH3. Doses of gamma-radiation 20-50 Gy were shown to inhibit proliferation and induce apoptosis in GH3 cells regardless of somatostatin presence. It has been found that the D(0) value for GH3 cells was 2.5 Gy. Somatostatin treatment increased radiosensitivity of GH3 cells, so that D(0) value decreased to 2.2 Gy. We detected quick phosphorylation of histone H2A.X upon irradiation by the dose 20 Gy and its colocalization with phosphorylated protein Nbs-1 in the site of double strand break of DNA (DSB). Number of DSB decreased significantly 24 h after irradiation, however, clearly distinguished foci persisted, indicating non repaired DSB, after irradiation alone or after combined treatment by irradiation and SS14. We found that SS14 alone triggers phosphorylation of Nbs1 (p-Nbs1), which correlates with antiproliferative effect of SS14. Irradiation also increased the presence of p-Nbs1. Most intensive phosphorylation of Nbs1 was detected after combined treatment of irradiation and SS14. The decrease of the number of the DSB foci 24 h after treatment shows a significant capacity of repair systems of GH3 cells. In spite of this, large number of unrepaired DSB persists for 24 h after the treatment. We conclude that SS14 does not have a radioprotective effect on somatomammotroph GH3 cells.

• MeSH
• adenom hypofýzy vylučující růstový hormon farmakoterapie   chirurgie   MeSH
• akromegalie farmakoterapie   chirurgie   MeSH
• apoptóza genetika   účinky záření   MeSH
• buněčný cyklus fyziologie   účinky záření   MeSH
• experimentální radiační poranění prevence a kontrola   MeSH
• histony metabolismus   účinky záření   MeSH
• ionizující záření MeSH
• jaderné proteiny metabolismus   účinky záření   MeSH
• krysa rodu rattus MeSH
• modely nemocí na zvířatech MeSH
• nádorové buněčné linie MeSH
• nádory hypofýzy farmakoterapie   chirurgie   MeSH
• neparametrická statistika MeSH
• poškození DNA fyziologie   účinky léků   MeSH
• potkani Wistar MeSH
• proteiny buněčného cyklu metabolismus   účinky záření   MeSH
• radiochirurgie škodlivé účinky   MeSH
• somatostatin fyziologie   terapeutické užití   MeSH
• somatotropní buňky metabolismus   účinky léků   účinky záření   MeSH
• zvířata MeSH
• Check Tag
• krysa rodu rattus MeSH
• zvířata MeSH