GH substitution does not alter the pulsatile pattern of LH in amenorrhoeic growth hormone deficient women.
OBJECTIVE
GH substitution in GH-deficient (GHD) children promotes pubertal development. In some GHD women, secondary amenorrhoea occurs after discontinuation of GH treatment. This study was designed to investigate whether GH substitution directly influences the GnRH pulse generator. For this reason, the pulsatile release of LH was studied in amenorrhoeic GHD women before and during GH substitution.


METHODS
GH deficiency was confirmed by an insulin tolerance test. During a 24-h period, blood samples were drawn every 10 min for determination of LH, FSH and GH levels. Oestradiol and IGF-1 were determined at 1000 h and 2200 h. After the first test day, patients started with GH substitution, 0.25 IU/kg/week. During month 6 of GH treatment, the 24 h blood sampling was repeated.


METHODS
Ten amenorrhoeic GH-deficient women participated in the trial. All were diagnosed as GH deficient during childhood or adolescence. Eight of them had been treated with GH during childhood. Seven women suffered from primary amenorrhoea and three from secondary amenorrhoea. Six women were started with GH substitution after the first test day (according to randomization in a larger study).


METHODS
LH and GH were determined every 10 min and FSH every 60 min. LH pulse detection was conducted using a validated statistical method.


RESULTS
Prior to GH treatment, the LH pulse interval did not show a diurnal pattern as found during normal pubertal development. During GH treatment, IGF-1 levels rose significantly. No differences were found in mean LH, LH pulse amplitude and LH pulse interval before and during GH treatment. Oestradiol levels did not change either.


CONCLUSIONS
GH substitution in amenorrhoeic GH-deficient women does not alter the pulsatile pattern of LH. This may suggest that GH treatment does not influence central nervous system control of gonadotropin secretion in GHD patients.
de Boer
J A
JA
Division of Reproductive Endocrinology and Fertility, Department of Obstetrics and Gynaecology, Institute of Endocrinology, Reproduction and Metabolism, Amsterdam, The Netherlands.
van der Veen
E A
EA
Schoemaker
J
J
D000328:Adult; D000568:Amenorrhea / Q000503:physiopathology*; D004958:Estradiol / Q000097:blood; D005260:Female; D005640:Follicle Stimulating Hormone / Q000097:blood; D013006:Growth Hormone / Q000097:blood / Q000172:deficiency*; D020249:Hormone Replacement Therapy; D019382:Human Growth Hormone / Q000627:therapeutic use; D006801:Humans; D007334:Insulin-Like Growth Factor I / Q000032:analysis; D007986:Luteinizing Hormone / Q000097:blood / Q000378:metabolism*; D012636:Secretory Rate; D018709:Statistics, Nonparametric
D019382:Human Growth Hormone; D004958:Estradiol; D007334:Insulin-Like Growth Factor I; D007986:Luteinizing Hormone; D005640:Follicle Stimulating Hormone; D013006:Growth Hormone