Regional Specificity in the Effect of Estrogen Implantation within the Forebrain on the Frequency of Pulsatile Luteinizing Hormone Secretion in the Ovariectomized Rat

Publisher Website
Google Scholar
Abstract
Pulsatile secretion of luteinizing hormone (LH) in ovariectomized rats was evaluated before and after local implantation of crystalline estradiol benzoate (EB) into various regions within the forebrain. Serum concentrations of LH were measured by radioimmunoassay in samples collected at 6-min intervals through indwelling cardiac catheters. In rats with EB implanted in the preoptic suprachiasmatic area (POSC), and in the nucleus of the tractus diagonalis and the diagonal band of Broca (DBB) to a lesser extent, the mean LH concentration and LH pulse frequency decreased rapidly while the pulse amplitude did not change for 3 h after implantation. Rats with the EB implant in the bed nucleus of stria terminals, the medial preoptic area, the medial septal nucleus, the anterior hypothalamic area or the 3rd ventricle showed unchanged frequencies of LH secretory pulses. Implantation of progesterone into the POSC of ovariectomized rats produced no significant change in LH secretory profiles. The sites of action of estrogen in decreasing the LH pulse frequency apparently are not widespeard but rather restricted within a small part of the brain including the POSC, and DBB, in the ovariectomized rat.

This publication has 14 references indexed in Scilit: