Mechanisms by which neonatal testosterone exposure mediates sex differences in impulsivity in prepubertal rats

• Published in: Hormones and behavior 2013-11, Vol.64 (5), p.764-769
• Main Authors: Bayless, Daniel W., Darling, Jeffrey S., Daniel, Jill M.
• Format: Article
• Language: English
• Subjects: Animal behavior; Animals; Animals, Newborn; Aromatase inhibitor; Behavior, Animal - drug effects; Behavioral psychophysiology; Biological and medical sciences; Choice Behavior - drug effects; Dihydrotestosterone; Estradiol; Female; Fundamental and applied biological sciences. Psychology; Gender differences; Hormones and behavior; Impulsive Behavior - chemically induced; Impulsive choice; Impulsivity; Male; Neonatal; Organizational effect; Prefrontal cortex; Psychology. Psychoanalysis. Psychiatry; Psychology. Psychophysiology; Rats; Rats, Long-Evans; Rodents; Sex difference; Sex Factors; Sexual Maturation - drug effects; Testosterone; Testosterone - pharmacology
• ISSN: 0018-506X; 1095-6867
• DOI: 10.1016/j.yhbeh.2013.10.003

Neonatal testosterone, either acting directly or through its conversion to estradiol, can exert organizational effects on the brain and behavior. The goal of the current study was to examine sex differences and determine the role of neonatal testosterone on prefrontal cortex-dependent impulsive choice behavior in prepubertal rats. Male and female prepubertal rats were tested on the delay-based impulsive choice task. Impulsive choice was defined as choosing an immediate small food reward over a delayed large reward. In a first experiment to examine sex differences, males made significantly more impulsive choices than did females. In a second experiment to examine the organizational effects of testosterone, females treated with neonatal testosterone made significantly more impulsive choices than did control females and their performance was indistinguishable from that of control males. In a third experiment to determine if the effect of testosterone on performance is due to the actions of androgens or estrogens through its conversion to estradiol, males treated neonatally with the aromatase inhibitor formestane, which blocks the conversion of testosterone to estradiol, females treated neonatally with the non-aromatizable androgen dihydrotestosterone, and females treated neonatally with estradiol made significantly more impulsive choices than did control females and their performance was indistinguishable from that of control males. Results indicate that male pubertal rats display increased impulsive choice behavior as compared to females, that this sex difference results from organizing actions of testosterone during the neonatal period, and that this effect can result from both androgenic and estrogenic actions. •We examined sex differences and organizational impact of testosterone on impulsivity.•Prepubertal male rats made more impulsive choices than did prepubertal female rats.•Neonatal testosterone exposure masculinized the female impulsive choice behavior.•The effect also occurred following exposure to estrogens or non-aromatizable androgens.•Our findings extend the impacts of neonatal gonadal hormones to impulsive behavior.