Abstract
It is known that pulsatile secretion of gonadotropin reflects hypothalamic LH-RH secretion. LH pulsatile secretion during the night starts to appear in the prepubertal period. However, little information is available in regard to the LH pulse in patients with amenorrhea in adolescent girls. In the present study, nocturnal LH pulsatile secretion was measured in patients with hypothalamic amenorrhea, and the relationship between LH pulsatile secretion and grade of amenorrhea was determined. Thirty-five patients with hypothalamic amenorrhea were divided into Group I (n=21) and Group II (n=14) by a progestogen test. Group I patients were sub-classified into two groups according to the response to clomiphene citrate (CC) ; CR (n=5) successfully ovulated by CC, and CNR (n=7) did not ovulate. Blood samples were collected from the patients every 20 min. from 20: 00 pm to 6: 00 am. Serum hormone levels were measured by radioimmunoassay and LH pulsatile secretion was compared with normal healty women (n=6) . Informed consent was obtained from all the patients and their parents. 1) Nocturnal mean estradiol levels and LH pulse frequency were significantly lower in Group II than those in Group I. Although nocturnal LH pulsatile secretion in Group I was near normal, Group II was characterized by a significantly low frequency and a similar amplitude compared with Group I. 2) There was no obvious change in estradiol levels while significantly lower basal LH levels and frequency and amplitude of LH pulse was observed in CNR. The LH pulsatile secretion in CNR was similar to that in Group II . From the results obtained above, it is suggested that the CNR patients might have an impaired estrogen feedback mechanism in addition to a disorder of LH pulse generator.
