ABSTRACT
Objective To analyse the clinical significance of LHRH exciting test in the differential diagnosis of constitutional delayed puberty (CDP) and hypogonadotropic hypogonadism (HH). Methods Eighty-one cases from 1982 to 1998 were investigated and followed up. They were all at genital stage Ⅰ. After injection of 100 ?g LHRH, the blood samples (3 ml) were taken at -15, 0, 15, 30, 45, 60, 90 and 120 min. The serum LH and FSH levels were determined by radioimmunoassay. Then they were followed up every 3-24 months. After they received LHRH exciting test, they were followed up until over 18 years old. According to their puberty development status, they were divided into 3 groups, normal group (n=34),CDP group (n=16) and HH group (n=31),andthemeanage,whenthey received LHRH exciting test, was (10.2?0.9, range 9-14) years, (16.0?1.0, range 14-18) years and (17.1?1.4, range 16-22) years respectively. Results There were no significant differences in serum LH baseline level and peak time in normal, CDP and HH groups, but the serum LH peak level, LH increment (peak LH level minus baseline LH level), LH increment ratio (peak level/baseline level of LH) and the area under LH curve (AUC LH ) of normal group were significantly higher than those of CDP group and HH group (all P
