Prolactin-Releasing Effect of Buspirone in Developing and Adult Male and Female Rats

Abstract

The prolactin-releasing effects of buspirone, an azaspirodecanedione anxiolytic drug unrelated to the benzodiazepines in structure and pharmacologic properties, was examined in developing and adult male and female rats. The possibility that effects of this drug on hormone release could be modulated by neonatal brain sexual differentiation was also evaluated.

A single injection of buspirone, 2 or 10 mg/kg body wt, increased serum prolactin (PRL) levels in both sexes; the increase was significant from Day 12 onward. The PRL-releasing effect increased with age. No significant sexual differences were observed in younger rats, but in peripubertal and adult animals, the hyperprolactinemic response was higher in the female. Neonatal androgenization of females or orchidectomy of males failed to modify the PRL-releasing action of buspirone.

Serum titers of luteinizing hormone and follicle-stimulating hormone were not modified by buspirone at any age.

The present results show for the first time the ontogeny of the PRL-releasing effect of buspirone in male and female rats, and provide evidence that the response is higher in the female and that the effect does not depend on brain sexual differentiation.