Corticosterone administration to rat pups, but not maternal separation, affects sexual maturation and glucocorticoid receptor immunoreactivity in the testis

Prenatal stress strongly affects sexual dimorphism of male rats. Much less information is instead available on the effects of postnatal stress on sexual maturation during the so-called stress hyporesponsive period (SHRP). For this reason, we compared corticosterone-treated (CS; 10 mg/kg sc, suspended in sesame oil) or maternally separated pups (MS; 5 h/day in the first week of life) with control rats. Control and MS pups also received sesame oil injections. The effects of these procedures on physical development (body weight and eye opening), sexual maturation [anogenital distance, testis weight, 3β-hydroxysteroid dehydrogenase/ Δ5–4 (3βHSD) isomerase activity and time to testis descent] and glucocorticoid receptor (GR) immunoreactivity in the testis were examined. Corticosterone treatment significantly ( P