Effects of the gonadotropin-releasing-hormone agonist, D-Trp-6-GnRH, on prolactin secretion in healthy young men.
The objective of this study was to examine the changes in basal plasma gonadotropin, alpha-subunit, sex steroids, and prolactin levels and the prolactin and luteinizing hormone (LH) secretion pattern before, during and 161 days after treatment with a depot preparation of D-Trp-6-GnRH in young men. Gonadotropins, alpha-subunit, sex steroids, and prolactin were measured in pooled plasma samples. Additionally, before treatment, several times during its course and on day 161 after treatment, blood samples were drawn for 8 h every 15 min for prolactin and LH measurements. After initial stimulation of the pituitary, administration of a depot preparation of D-Trp-6-GnRH resulted in a constant decrease in gonadotropin and sex steroid concentrations with LH and testosterone concentrations remaining within the limits of prepubertal levels from days 16 to 48. Alpha-Subunit concentrations (0.4 +/- 0.09 IU/l; mean +/- SE) increased after application of D-Trp-6-GnRH, and remained elevated until day 48. Basal prolactin levels (3.5 +/- 0.25 microgram/l) did not change significantly during treatment but afterwards increased consistently with maximal levels at day 141 (15.3 +/- 3.8 microgram/l); they had decreased at day 161 to 10.3 +/- 1.8 microgram/l which is significantly higher than before treatment (p < 0.05). On day 161, prolactin pulse amplitude was significantly higher than before and during treatment (p<0.05), while no significant changes in pulse frequency occurred. No significant temporal coupling between LH and prolactin release could be detected.(ABSTRACT TRUNCATED AT 250 WORDS)
Stoffel-Wagner
B
B
Department of Clinical Biochemistry, University of Bonn, Germany.
Sommer
L
L
Bidlingmaier
F
F
Klingmüller
D
D
D000328:Adult; D003692:Delayed-Action Preparations; D004958:Estradiol / Q000097:blood; D005640:Follicle Stimulating Hormone / Q000097:blood; D015292:Glycoprotein Hormones, alpha Subunit / Q000097:blood; D006801:Humans; D007700:Kinetics; D007986:Luteinizing Hormone / Q000097:blood / Q000378:metabolism; D008297:Male; D011388:Prolactin / Q000097:blood / Q000378:metabolism*; D013739:Testosterone / Q000097:blood; D017329:Triptorelin Pamoate / Q000009:adverse effects / Q000494:pharmacology*
D003692:Delayed-Action Preparations; D015292:Glycoprotein Hormones, alpha Subunit; D017329:Triptorelin Pamoate; D013739:Testosterone; D004958:Estradiol; D011388:Prolactin; D007986:Luteinizing Hormone; D005640:Follicle Stimulating Hormone