Effects of pinealectomy and continuous light on mating behavior of male rats

The role of pinealectomy and continuous light in the regulation of sexual activity was studied in the male rat. The parameters studied in order to evaluate the sexual behavior were initial latency, ejaculatory latency, refractory period, neuromotor activity, number of ejaculations, intromissions (false, real, and total) and percentage of ejaculating male rats. Pinealectomy as well as continuous light induced a marked facilitation of the animal's sexual behavior as shown by the shorter initial latency and refractory period, as well as by the increase in the number of intromissions (real and total) showed in the tests. However, the ejaculatory latencies did not change. There was also an enhanced neuromotor activity. An increase in the number of ejaculations as well as in the percentage of ejaculating male rats was produced by continuous light. From the results it is concluded that pineal hormones play an important role in male rat sexual behavior.