title: The effects of pulsatile GnRH infusion upon the diurnal variations in serum LH and testosterone in pre-pubertal and pubertal boys.
abstract: 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.
authors.affiliation: University Department of Medicine, Royal Infirmary, Glasgow.
authors.forename: D
authors.initials: D
authors.lastname: Gordon
authors.forename: C E
authors.initials: CE
authors.lastname: Gray
authors.forename: G H
authors.initials: GH
authors.lastname: Beastall
authors.forename: J A
authors.initials: JA
authors.lastname: Thomson
mesh_terms: 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*
chemical_list: D010906:Pituitary Hormone-Releasing Hormones; D013739:Testosterone; D007986:Luteinizing Hormone