Postnatal Treatment of Rats with Beta-adrenergic Agonists or Antagonists Influences Differentiation of Sexual Brain Functions^*)

Summary

Sexual differentiation of the brain seems to be influenced by postnatal interaction of gonadal steroids with neurotransmitter systems, in particular the adrenergic system. Stimulation or inhibition of α-adrenergic receptors during early postnatal development had previously been shown to influence steroid-induced sexual differentiation of brain functions. In the present study newborn male and female rats were treated either with salbutamol, a selective β₂-adrenergic receptor agonist, isoprenaline, a general β-adrenergic receptor agonist, or with alprenolol, a general β-adrenergic receptor antagonist. In adulthood the female animals were ovariectomized and were tested for the capacity to show an LH-surge response and female sexual behavior after priming with estradiol ben-zoate (EB) and progesterone (P). Male animals were tested for expression of male sexual behavior and, after gonadectomy and priming with EB + P, for the capacity to show female lordosis behavior.

In summary, our results suggest that activation or inhibition of β-adrenergic receptors during postnatal development permanently impairs the responsiveness of the center for cyclic gonadotropin release to gonadal steroids in female rats and impairs the expression of ejaculatory behavior in male rats. A slight stimulatory effect on the expression of female lordosis behavior was observed in male and female rats after postnatal activation of β-adrenergic receptors.

Key words

Adrenergic receptors - Alprenolol - Isoprenaline - Luteinizing hormone - Salbutamol - Sexual behavior - Sexual differentiation