Ovarian Membrane Receptors for LH, FSH and Prolactin during the Menstrual Cycle and in Polycystic Ovary Syndrome

OTA, H., FUKUSHIMA, M., MURATA, J., WAKIZAKA, A. and MAKI, M. Ovarian Membrane Receptors for LH, FSH and Prolactin during the Menstrual Cycle and in Polycystic Ovary Syndrome. Tohoku J. exp. Med., 1986, 149 (3), 231-240-To investigate the role of ovarian membrane receptors for LH, FSH and prolactin of patients with developing Polycystic ovary (PCO) syndrome, seven patients were selected and the receptor function was studied in relation to changes of several serum hormone levels. The results were compared with those from individuals with regular menstrual cycles in the late follicular (LF; n=6) and midluteal (ML; n=6) phases. LH receptor binding in the normal cycle remained low (1.73±0.14fmole/mg homogenate protein) in the LF phase and elevated 3 fold in the ML phase. LH receptors in the PCO patients maintained a higher binding level than that in the LF phase, being close to the ML level. FSH receptors were at a high level in the LF phase (4.09±0.40fmole/mg homogenate protein), but decreased by 23% in the ML phase. In the PCO group the ovarian FSH receptor showed a high level, near to that in the LF phase. Prolactin receptors showed no significant changes among the two controls and PCO group. PCO patients showed increased levels of serum LH and testosterone and a raised ratio of estrone to estradiol, although there was no change in the serum FSH level. These data suggested that the LH receptor binding in PCO was not so low as to the LF level. A lack of the down-regulation mechanism of LH receptors, in spite of the high level of serum LH in PCO, might be one of the clues to elucidate the pathophysiological mechanism in developing PCO syndrome. Elevated levels of the gonadotropin receptors, especially FSH receptors, seem to be involved in the high incidence of ovarian hyperstimulation during hormone treatment.