Involvement of the cholinergic system in the precocious puberty caused by estradiol in immature female rats.

Subcutaneous administration of 0.05 mug estradiol benzoate to sexually immature female rats caused precocious ovulation and a decreased acetylcholine content in the hypothalamus and the amygdala. A higher dose of estradiol benzoate, 2 mug/rat, did not stimulate ovulation but did cause a further decrease in the acetylcholine content in the hypothalamus and the amygdala. The steady state levels of acetylcholine in the hippocampus and the striatum were unchanged with either dose of estradiol. These observations suggest a relationship between the occurrence of ovulation and the decrease in the steady state level of acetylcholine in the hypothalamus and amygdala in sexually immature rats after estradiol treatment.