Radioimmunoassay of the changes in the pituitary-gonadal axis following acute gamma irradiation

Data are reported on the content of gonadal axis hormones - lx, fsh and testosterone on the blood plasma of rats after acute gamma-irradiation with dose emissive power 1,26 Gy/min and doses 0,5, 1,0 , 2,0 and 4,0 Gy. Animals were examined on the irradiation day on the 2-nd, 3-rd, 6-th, 12-th, 20-th, 30-th and 40-th post-irradiation day. After exposure to each dose and on the respective day 10 animals were sacrificed, and by radioimmunoassay the plasma content of the hormones mentioned above was determined. Correlation was found between the levels of lx and fsh, and the level of testosterone. In the first three post exposure days dynamic variations were observed - decrease in the lx and fsh levels and a rise in that of testosterone, which was dose-dependent. After the third day the testosterone level in animals gamma-irradiated with 0,5 Gy dose remained significantly higher than the normal one. Similar was the pattern in animals exposed to 1,0 Gy gamma rays until the 20-th day, whereupon the testosterone level dropped to much lower than the normal one. After the third day the plasma content of the pituitary hormones was strongly reduced after animal exposure to any of the doses. By the 20-th day a slight tendency was observed toward return to normal, but this was followed by decrease anew, till the end of the study period