Related Experiment Videos
[Endocrinological background of pituitary desensitization during pulsatile LH-RH therapy for ovulation induction in
1Department of Obstetrics and Gynecology, Gunma University School of Medicine, Maebashi.
Abstract:
In order to elucidate the endocrinological background of patients in whom ovulation induction by pulsatile LH-RH administration resulted in failure, 16 women with hypothalamic amenorrhea were treated with 10 to 20 micrograms of LH-RH injected subcutaneously every 2 hrs. Six women did not ovulate, and 5 of them showed pituitary desensitization since the basal gonadotropin concentration gradually decreased and the response to LH-RH test (100 micrograms i.v.) became blunted by the treatment. No significant differences between the ovulated and desensitized groups were seen in basal LH, FSH, E2, PRL levels, LH/FSH ratio and response to LH-RH test performed prior to the treatment. In addition, the plasma LH-RH profile after subcutaneous injection of 10 micrograms of LH-RH was highly pulsatile in both groups. However, in the desensitized group, all were obese, showed impaired GH response to both insulin tolerance and GH-RH tests, and had episodic LH secretion with higher frequency compared to the ovulated group. These results suggest that the desensitized women had occult pituitary dysfunction and hypersecretion of endogenous LH-RH which stimulated the pituitary close to the level of desensitization. The mechanism of hypersecretion of endogenous LH-RH is discussed.
Insights
Pulsatile gonadotropin-releasing hormone (GnRH) therapy for hypothalamic amenorrhea can fail due to pituitary desensitization. Obese women with impaired GH response and frequent LH secretion may be at higher risk for this treatment failure.
Area of Science:
- Endocrinology
- Reproductive Medicine
Background:
- Pulsatile administration of luteinizing hormone-releasing hormone (LH-RH) is a standard treatment for ovulation induction in women with hypothalamic amenorrhea.
- Understanding the endocrinological factors contributing to treatment failure is crucial for optimizing patient outcomes.
Purpose of the Study:
- To investigate the endocrinological background of patients experiencing failed ovulation induction with pulsatile LH-RH therapy.
- To identify potential markers or characteristics associated with pituitary desensitization during treatment.
Main Methods:
- 16 women with hypothalamic amenorrhea received subcutaneous LH-RH (10-20 µg) every 2 hours.
- Basal hormone levels (LH, FSH, E2, PRL), LH/FSH ratio, and responses to LH-RH tests were assessed.
- Plasma LH-RH profiles and growth hormone (GH) responses were evaluated in subgroups.
Main Results:
- Six women (37.5%) did not ovulate; 5 of these developed pituitary desensitization, evidenced by decreased gonadotropin levels and blunted LH-RH test responses.
- No significant pre-treatment differences were observed between ovulated and desensitized groups in basal hormones or initial LH-RH test responses.
- The desensitized group exhibited obesity, impaired GH response, and more frequent episodic LH secretion compared to the ovulated group.
Conclusions:
- Pituitary desensitization during pulsatile LH-RH therapy may indicate underlying pituitary dysfunction and endogenous LH-RH hypersecretion.
- Obesity and impaired GH secretion could be associated with the risk of developing pituitary desensitization in this patient population.
- Further research is needed to elucidate the mechanisms of endogenous LH-RH hypersecretion and its role in treatment failure.