Effects of Pre-exposure Mouse Pituitary with Low-dose ^60Co γ-ray on Growth Hormone （GH） and Body Mass Induced by Subsequent High-dose Irradiation

The pituitary of the B6C3F1 hybrid strain mice were irradiated with 0.05 Gy of ^60Co γ-ray as the pre-exposure dose (D1), and were then irradiated with 2 Gy of ^60Co γ-ray as challenging irradiation dose (D2) at 4h after per-exposure. Body weight and serum growth hormone (GH) were measured at 35th day after irradiation. The results showed that irradiation of mouse testes with 2 Gy of ^60Co γ-ray significantly diminished mousebody weight and level of serum GH (Table). Pre-exposure with a low-dose (0.05 Gy) of ^60Co γ-ray significantly alleviated reductions of mouse body weight and level of serum GH induced by subsequent a high-dose (2 Gy) irradiation (Table). The data suggested that low-dose ionizing irradiation can induce adaptive responses to the harmful effects of pituitary by subsequent high-dose exposure.     

Research of Effect of ^60Co γ-ray Irradiation on Cell Cycle of SMMC, 7721 Tumor Cell with Flow Cytometery

The resultsMost researchof cell cycle play an important role in resear, ching tumor occurrence, development and treatment. results show that malignant grade and pharmic sensitivity of tumor are relative to cell cycle. The sensitivity of medications is different to different phases of cell cycle of tumor. In general, the cell of M are more sensitivity. On the side, different medications have different action in different cell cycle. The irradiation can change cell cycle proccss and can induce the pattern of changes in cell cycle. For cxamplc, G1 arrest, G2 arrest and S arrest. So, thc research rcsults of tumor cell cycle in different irradiation have not only biological means but also realistic means for selecting chemical therapy medication after radiotherapy.