Inhibition of the preovulatory LH surge after a catecholestrogen (2-hydroxyestrone) antiserum injection in the third ventricle of cycling female rats

Abstract Administration of a catecholestrogen (2-hydroxyestrone, 2-OHE 1 ) antiserum (2-OHE 1 -AS) in the third ventricle of cycling female rats, on the morning of proestrus, leads to a significant reduction in the afternoon LH surge. These responses are dose-dependent and can be observed even when the 2-OHE 1 -AS is injected on the diestrus morning. Almost similar results were obtained with an antiserum against 17β-estradiol (17β-E 2 ). Nevertheless, the fact that the central immunoneutralization of 2-OHE 1 impedes the preovulatory surge of LH at a time of high peripheral levels of 17β-E 2 strengthens the idea of a specific role for 2-OHE 1 in the control of cycling LH release.