Effect of irradiation of the brain tumor with X-ray and heavy ion on sexual behavior.

重离子照射大脑对性行为的影响尚不清楚。本研究旨在探讨大鼠下丘脑照射(碳粒子，290 MeV/核子，单峰15~120Gy，照射野5-mm^3)对雄性大鼠交配行为的影响。我们计划用一个相对较高的剂量来评估碳辐射对交配行为的短期影响，并在照射后1、2或3个月进行30min的性行为观察。结果表明：1.在15Gy30Gy45Gy60Gy4个剂量下，照射后1个月交配行为没有变化；然而，60Gy2大鼠经3个月随访后，插入和射精明显减少。在较高剂量(90Gy120Gy2)下，坐位次数、插入次数(单独120Gy值)和射精数(90Gy120Gy值)均减少。根据上述实验结果，可以确定碳束照射下丘脑在短时间内不抑制交配行为的活动。为了确定重离子对交配行为的慢性影响，必须进行进一步的实验，这些实验需要在照射后进行长期跟踪。

The effect of heavy-ion irradiation to the brain on sexual behavior is not yet known. The present study was designed to determine whether irradiation (carbon particles,290 MeV/nucleon, Mono peak 15~ 120 Gy,irradiation field 5-mm^3 in hypothalamus) to rat's hypothalamus modifies copulatory behavior of male rats. We planned to estimate the short-term effects of carbon-irradiation on copulatory behavior using a relatively high doses, and observation of sexual behavior was conducted for 30 min after 1,2 or 3 months following irradiation.Results obtained are as follows :1.At dosages of 15Gy,30Gy,45Gy and 60Gy, these were no changes in copulatory behavior after 1 month following irradiation ; however, intromission and ejaculation were found to decrease after 3-month follow-up in rats exposed to 60 Gy.2.At higher doses such as 90Gy,120Gy, the number of mounting, intromission (120Gy alone) and ejaculation (90Gy,120Gy) were decreased.From the experimental results described above, it may be possible to determine that carbon beam irradiation to hypothalamus does not inhibit the activity of copulatory behavior for a short period after irradiation. Further experiments that need long-term follow-up after irradiation must be necessary to determine the chronic effects of heavy ions on the copulatory behavior.