Correlation between changes in LH-RH content in the synaptosomal fraction of the olfactory bulb and some hypothalamic zones and level of sexual activity in male rats.

We have studied the level of LH-RH in the synaptosomal fraction of the olfactory bulbs, preoptic area, and mediobasal hypothalamus, and the blood level of HL in adult male rats with sexual activity after noradrenergic denervation of the preoptic area using 6-oxydopamine. A neurotoxic effect of a 0.1% solution of ascorbic acid, preventing 6-oxydopamine disintegration was observed. Both sexual activity and level of LH-RH in synaptosomes of the preoptic area were reduced in male rats with noradrenergic denervation of the preoptic area. The maximum blood level of LH was observed during exposure to a recipient female rat, the LH-RH concentration in the synaptosomal fraction of the olfactory bulbs being raised, and that in the mediobasal hypothalamus being decreased. The results showed that LH-RH synthesizing cerebral neurons with terminals in the olfactory bulbs, preoptic area, and mediobasal hypothalamus are involved in the regulation of sexual behavior and the interaction of LH-RH-containing terminals with noradrenergic nerve endings at the level of the preoptic area.