Summary
The role of postnatal ovary in the maturation of estradiol (E2)-induced luteinizing hormone (LH) and prolactin (PRL) surges was examined in female
rats of Wistar-Imamichi strain. Animals were bilaterally ovariectomized at 24 h after
birth, 1 week (w), 2 w, 3 w, 4 w or 6 w of age. At about 10 w of age, every group
was primed with estradiol benzoate (E2 B) for two days, and on the third day was decapitated at either 0900 h or 1900 h.
Anterior pituitary (AP) LH and PRL content was determined in every group of no E2B treatment. Surge-like secretions of LH and PRL were observed at 1900 h, only in
rats ovariectomized on or after 4 w of age. AP LH and PRL content was the higher,
as ovariectomy was delayed. These results indicate that postnatal ovary is necessary
for the maturation of E2-induced LH and PRL surges. Such an effect of ovary is mediated at least by its stimulation
of AP LH and PRL content.
Key-Words
Estradiol
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Surge
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Luteinizing Hormone
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Prolactin
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Postnatal Ovary
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Sexual Differentiation