Disruptive effects of neonatal gonadectomy on adult sexual partner preference and brain dimorphism in male rats: partial restoration with pubertal testosterone

• Published in: Behavioural brain research 2019-11, Vol.374, p.112117-112117, Article 112117
• Main Authors: Barradas-Moctezuma, Miriam, Herrera-Covarrubias, Deissy, Manzo, Jorge, Coria-Avila, Genaro A.
• Format: Article
• Language: English
• Subjects: Brain dimorphism; Castration; Organizational hypothesis; Partner preference; Sex; Testosterone
• ISSN: 0166-4328; 1872-7549
• DOI: 10.1016/j.bbr.2019.112117

•Neonatal gonadectomy (Gnx PD1) impaired partner preference and brain dimorphism in adulthood.•Testosterone during puberty restored preference and brain dimorphism of GNX PD1 males.•Gnx PD1 impairs sexual partner preference and brain dimorphism, but pubertal testosterone reverses the effects. According to the organizational-activational hypothesis, testosterone or its metabolite estradiol, can organize the brain in a male direction (permanently or for long periods) if exposure occurs during a critical (sensitive) time of brain development like the prenatal period. Male rodents with insufficient levels of testosterone during such critical period would irreversibly fail to display sexual partner preference for receptive females in adulthood. However, exposure to testosterone during puberty is believed to function as a second critical period for organization of brain and behavior. Thus, in the present study we explored the effects of neonatal gonadectomy at postnatal day 1 (GNX) on the partner preference of adult males and the size of some sexually dimorphic regions in the brain like the SDN-MPOA, SCN, MeApd and VMH; and challenged its irreversibility by providing exogenous testosterone during puberty. Our results indicated that neonatal GNX impaired partner preference for females and reduced the size of SDN-MPOA, MeApd and VMH, but not SCN. GNX males restored with testosterone in PD30-PD59 (GNX + T) expressed partner preference for sexually receptive females and increased the size of SDN-MPOA and VMH, but not MeApd in adulthood. We conclude that neonatal castration and the lack of testosterone during the first month of life alters sexual behavior and brain dimorphism in adult male rats, but pubertal testosterone reverses the effects on behavior and brain dimorphism to some extent.