Neonatal androgen effects on conditioned emotional response extinction of adult rats under various hormonal regimens

Intact male rats and spayed female rats received 0.5 mg testosterone propionate in the first 24 hours after birth. They were divided into different groups, administered peanut oil, progesterone, oestradiol benzoate and testosterone propionate in adulthood. The animals were conditioned to fear with a shock paired sound. The experimental test consisted of investigating the conditioned emotional response (CER) extinction. It was verified that as to conditioned emotional response extinction, neonatally androgenized males were different from control males; neonatally androgenized females, testosterone propionate treated in adulthood were also different from control females. There was no significant difference between neonatally androgenized females oestradiol benzoate treated in adulthood and their control group. In comparing neonatally androgenized females having different hormonal treatment in adulthood, we verified that testosterone propionate treated females were significantly different from those treated with progesterone. On the other hand, neonatally androgenized females treated with oestradiol benzoate in adulthood were different from those that have had the same hormonal manipulation in neonatal period, but that were injected with progesterone in adulthood. It was concluded that conditioned emotional response extinction is facilitated by neonatal androgenization in non-oestrogenized male and female rats.