Abstract
The effect of heavy-ion irradiation to brain on sexual behavior is not yet known. The present study was designed to determine whether irradiation (carbon particles 290 MeV/nucleon, Mono peak 15-120Gy, irradiation field 5-millimeter cube in hypothalamus) to rat's hypothalamus modifies the copulatory behavior of male rats.
We planned to estimate the short-term effects of carbon-irradiation on the 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 are as follows.
1) At dosages of 15Gy, 30Gy, 45Gy and 60Gy these were no changes in copulatory behavior after one month following irradiation; however, the intromission and ejaculation was found to decrease after 3-month follow-up in rats exposed to 60Gy.
2) At higher doses such as 90Gy, 120Gy, the number of mounting, intromission (120Gy alone) and ejaculation (90Gy, 120Gy) were decreased.
It may be possible to describe that carbon irradiation to hypothalamus does not inhibit the activity of copulatory behavior after short-term. Further experiments after long-term follow-up after irradiation are necessary to determine the chronic effects of heavy ions on the copulatory behavior.
