The effects of pulsatile GnRH infusion upon the diurnal variations in serum LH and testosterone in pre-pubertal and pubertal boys.
The aim of the present study was to determine the effects of exogenous GnRH pulsatile infusions on the diurnal variations of LH and testosterone secretion which occur in late pre-puberty and early puberty. GnRH infusions were administered to 12 short stature males in pre-puberty or early puberty, over 6-day periods. In 6 patients, GnRH doses of 2.5, 7.5 and 15 micrograms/pulse were used and 24-h profiles of serum LH and testosterone were measured before and at the end of the infusions. In the remaining 6 patients GnRH was administered at a dose of 7.5 micrograms/pulse and profiles between 21.00 and 06.00 h the following day were determined. Pre-infusion profiles demonstrated nocturnal LH and testosterone rises in all patients. Median pre-infusion serum LH prior to midnight was 2.2 U/l (range 1.0-5.4) rising to 3.7 U/l (range 1.9-10.7) during GnRH administration (p less than 0.005). After midnight, median pre-treatment serum LH concentration was 4.3 U/l (range 2.7-7.5) which remained unaltered by GnRH administration (median 4.8 U/l, range 2.9-7.9, p greater than 0.05). Median pre-therapy serum testosterone before midnight was 0.8 nmol/l (range 0.1-7.1) rising significantly (p less than 0.05) to 4.1 nmol/l (range 0.2-8.0). Following therapy, post-midnight median serum testosterone rose from 4.8 (range 0.4-9.4) to 7.0 nmol/l (range 0.5-13.9, p greater than 0.05). Diurnal variation in LH and testosterone secretion, therefore, is maintained during exogenous GnRH administration to pre-pubertal and pubertal boys. Response to exogenous GnRH pulses may be significantly influenced by endogenous GnRH.
Gordon
D
D
University Department of Medicine, Royal Infirmary, Glasgow.
Gray
C E
CE
Beastall
G H
GH
Thomson
J A
JA
D000293:Adolescent; D002648:Child; D002940:Circadian Rhythm; D006801:Humans; D007260:Infusion Pumps; D007986:Luteinizing Hormone / Q000097:blood*; D008297:Male; D010906:Pituitary Hormone-Releasing Hormones / Q000008:administration & dosage*; D011627:Puberty / Q000097:blood*; D013739:Testosterone / Q000097:blood*
D010906:Pituitary Hormone-Releasing Hormones; D013739:Testosterone; D007986:Luteinizing Hormone