Effect of selective midbrain and diencephalic 5,7-dihydroxytryptamine lesions on serotonin content in individual preopticohypothalamic nuclei and on serum luteinizing hormone level.

Injection of the serotonin neurotoxin, 5,7-dihydroxytryptamine (5,7-DHT), into the midbrain dorsal (DR) or median (MR) raphe nucleus of castrated and normal male rats was followed by measurement of serum luteinizing hormone (LH) level and the 5-hydroxytryptamine (5-HT) content of several hypothalamic and amygdaloid nuclei. Only the DR lesions lead to a significant decrease (42%) in serum LH level in normal rats. The elevated LH level in castrated animals was not affected by either lesion.