LONG-TERM ADMINISTRATION OF PULSATILE GONADOTROPIN-RELEASING-HORMONE FOR EXPLORATION OF PITUITARY FUNCTIONALITY IN AMENORRHEIC PATIENTS

Differentiation between hypothalamic and pituitary amenorrhea is gener ally based on the luteinizing hormone-releasing hormone (LHRH) test (w hether as a single nose, two consecutive doses, or pulsatile over 5-10 days), together with high-resolution imaging (computed tomography or magnetic resonance) of the sellar region. Long-term administration of gonadotropin-releasing hormone (GnRH) is generally used only for ovula tion induction, and not for diagnostic purposes. Here, we report the r esults of long-term administration of GnRH to 19 women initially diagn osed as suffering from hypothalamic amenorrhea on the basis of LHRH te sting and computed tomography imaging. During treatment, subjects rece ived 20-mu g pulses of GnRH every 90 min, subcutaneously from a portab le infusion pump. Fourteen subjects responded (i.e. ovulated) during t he first treatment cycle; one subject menstruated but did not ovulate during the first cycle, and then dropped out of the study; the remaini ng four subjects did not ovulate or menstruate despite at least three treatment cycles. Magnetic resonance imaging of the sellar region of t hese four subjects revealed pituitary lesions (partially empty sella i n three cases, microadenoma in one case) which had not been detected b y computed tomography. By contrast, no such abnormalities were detecte d in the nine responders who agreed to undergo magnetic resonance imag ing. These findings suggest that long-term administration of GnRH is o f value not only for ovulation induction but also for diagnostic purpo ses. Specifically, an initial diagnosis of hypothalamic amenorrhea is confirmed if there is a positive ovulation response after two GnRH tre atment cycles; otherwise, pituitary amenorrhea should be suspected. Ou r results also suggest that magnetic resonance imaging is more effecti ve than computed tomography for the detection of partially empty sella .