Naloxone stimulation test in women with hypothalamic amenorrhea: a preliminary report

Oral administration of a corticotropin-releasing hormone receptor antagonist significantly attenuates behavioral, neuroendocrine, and autonomic responses to stress in primates

We evaluated the effects of the lipophilic nonpeptide corticotropin-releasing hormone (CRH) type 1 receptor antagonist antalarmin on the behavioral, neuroendocrine, and autonomic components of the stress response in adult male rhesus macaques. After oral administration, significant antalarmin concentrations were detected in the systemic circulation and the cerebrospinal fluid by a mass spectrometry-gas chromatography assay developed specifically for this purpose. Pharmacokinetic and dose-response studies suggested that an oral dose of 20 mg/kg was optimal for behavioral and endocrine effects. We then administered this dose in a double-blind, placebo-controlled fashion to monkeys exposed to an intense social stressor: namely, placement of two unfamiliar males in adjacent cages separated only by a transparent Plexiglas screen. Antalarmin significantly inhibited a repertoire of behaviors associated with anxiety and fear such as body tremors, grimacing, teeth gnashing, urination, and defecation. In contrast, antalarmin increased exploratory and sexual behaviors that are normally suppressed during stress. Moreover, antalarmin significantly diminished the increases in cerebrospinal fluid CRH as well as the pituitary-adrenal, sympathetic, and adrenal medullary responses to stress. We conclude that CRH plays a broad role in the physiological responses to psychological stress in primates and that a CRH type 1 receptor antagonist may be of therapeutic value in human psychiatric, reproductive, and cardiovascular disorders associated with CRH system hyperactivity.

Long-term administration of pulsatile gonadotropin-releasing hormone for exploration of pituitary functionality in amenorrheic patients

Differentiation between hypothalamic and pituitary amenorrhea is generally based on the luteinizing hormone-releasing hormone (LHRH) test (whether as a single dose, 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 ovulation induction, and not for diagnostic purposes. Here, we report the results of long-term administration of GnRH to 19 women initially diagnosed as suffering from hypothalamic amenorrhea on the basis of LHRH testing and computed tomography imaging. During treatment, subjects received 20-micrograms pulses of GnRH every 90 min, subcutaneously from a portable infusion pump. Fourteen subjects responded (i.e. ovulated) during the first treatment cycle; one subject menstruated but did not ovulate during the first cycle, and the dropped out of the study; the remaining four subjects did not ovulate or menstruate despite at least three treatment cycles. Magnetic resonance imaging of the sellar region of these four subjects revealed pituitary lesions (partially empty sella in three cases, microadenoma in one case) which had not been detected by computed tomography. By contrast, no such abnormalities were detected in the nine responders who agreed to undergo magnetic resonance imaging. These findings suggest that long-term administration of GnRH is of value not only for ovulation induction but also for diagnostic purposes. Specifically, an initial diagnosis of hypothalamic amenorrhea is confirmed if there is a positive ovulation response after two GnRH treatment cycles; otherwise, pituitary amenorrhea should be suspected. Our results also suggest that magnetic resonance imaging is more effective than computed tomography for the detection of partially empty sella.