[Hypothalamo-hypophyseal amenorrhea. I. The clinical and laboratory manifestations]

This study included 15 women 18-36 years old with primary or secondary amenorrhea, low FSH and LH, a negative response to clormadinone and serum prolactin (Prl) levels less than 20.0 ng/ml. The following tests were performed on alternate days: LH and FSH determinations every 20 minutes (pulses) during 2-4 hours (n = 15); LH and FSH response to a single dose of GnRH 100 micrograms IV (n = 15) and after administration of 100 micrograms IM of GnRH daily during four consecutive days (n = 7); TRH test 200 micrograms IV (n = 9); oral metoclopramide-Prl induced response (10 mg) (n = 2); one to three basal determinations of cortisol, estradiol (E2), T3, T4, and TSH (n = 15). All patients had serum E2 levels less than 10.0 pg/ml and none showed a regular LH or FSH pulsatility. In seven patients (group A) serum LH had a 10-30 fold increase above basal levels in response to GnRH, while the other eight patients (group B) showed no response at all; serum FSH changes were most irregular in both group. In group A no other hormonal deficiencies were detected, while in group B only three patients had an isolated LH-FSH deficiency, and in the other five this deficiency was accompanied by Prl, TSH, and/or ACTH lack. The present results suggest that: 1) group A represents isolated GnRH deficiency and the amenorrhea has hypothalamic etiology; 2) group B had LH-FSH deficiency of pituitary origin, in most cases associated to other pituitary hormone deficiencies; 3) the lack of LH response to an initial single dose of GnRH is not an absolute indicator of hypophyseal amenorrhea.