[Endocrinological background of pituitary desensitization during pulsatile LH-RH therapy for ovulation induction in amenorrheic women].
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.
Obara
M
M
Department of Obstetrics and Gynecology, Gunma University School of Medicine, Maebashi.
Mizunuma
H
H
Ibuki
Y
Y
Igarashi
M
M
D000328:Adult; D000568:Amenorrhea / Q000188:drug therapy* / Q000503:physiopathology; D004351:Drug Resistance; D005246:Feedback; D005260:Female; D007987:Gonadotropin-Releasing Hormone / Q000008:administration & dosage / Q000378:metabolism / Q000627:therapeutic use*; D013006:Growth Hormone / Q000378:metabolism; D006801:Humans; D007986:Luteinizing Hormone / Q000097:blood / Q000378:metabolism; D010062:Ovulation Induction / Q000379:methods*; D010902:Pituitary Gland / Q000378:metabolism / Q000503:physiopathology*
D007987:Gonadotropin-Releasing Hormone; D007986:Luteinizing Hormone; D013006:Growth Hormone