Estrogen Effect to DNA Synthesis and Gonadotropin Production on Anterior Pituitary Gland

Abstract

Estrogen effect to DNA synthesis and LH production on the anterior pituitary cells were studied by the technique of autoradiogram, enzyme labelled antibody method and RIA with the castrated female rats.
Results are as follows;
1) Estradiol increases both LH content and DNA synthesis of anterior pituitary gland. Peak of DNA synthesis is 24 hrs. earlier than that of LH content.
2) When the endogenous LH-RH is blocked by the administration of chlorpromazine, the increase of LH content and DNA Synthesis in pituitary gland are still recognized.
3) After the LH-RH administration, pituitary LH content becomes relatively low level and peripheral serum LH level markedly increases.
4) In vitro experiment, estradiol has no influence to LH releasing rate.
5) DNA synthetic cells of anterior pituitary gland are chromophobe and they do not contain LH.
From above results, it was concluded that estradiol has direct action to anterior pituitary gland, that is, it increases in number of premonitory gonadotrophs, resulting in LH production after cellular maturity