Mediation by nitric oxide of LH-RH-stimulated gonadotropin secretions in human subjects.
In order to establish whether nitric-oxide (NO) participates in the regulation of gonadotropin secretion in humans, seven normal men were treated with a placebo (normal saline) or the NO synthase inhibitor L-NAME, given at doses (40 micrograms/kg injected plus 50 micrograms/kg infused i.v.) previously found to be unable to change blood pressure. Experiments were carried out either in basal conditions or during stimulation of gonadotropin secretion with an intravenous injection of 100 micrograms LH-RH. The administration of L-NAME was unable to change the basal secretion of FSH and LH. In contrast, L-NAME significantly reduced both FSH and LH increments induced by LH-RH. These data fail to provide evidence of NO involvement in regulation of basal gonadotropin secretion. In contrast, the inhibitory effect of L-NAME on LH-RH-induced LH and FSH secretion suggests the modulation by NO of the gonadotropin releasing action of LH-RH.
Chiodera
P
P
University Clinic of Endocrinology, University of Parma, Italy.
Volpi
R
R
Caffarri
G
G
Capretti
L
L
Magotti
M G
MG
Coiro
V
V
D000328:Adult; D004791:Enzyme Inhibitors; D005640:Follicle Stimulating Hormone / Q000378:metabolism*; D007987:Gonadotropin-Releasing Hormone / Q000494:pharmacology*; D006801:Humans; D007700:Kinetics; D007986:Luteinizing Hormone / Q000378:metabolism*; D008297:Male; D019331:NG-Nitroarginine Methyl Ester; D009569:Nitric Oxide / Q000502:physiology*; D019001:Nitric Oxide Synthase / Q000037:antagonists & inhibitors
D004791:Enzyme Inhibitors; D009569:Nitric Oxide; D007987:Gonadotropin-Releasing Hormone; D007986:Luteinizing Hormone; D005640:Follicle Stimulating Hormone; D019001:Nitric Oxide Synthase; D019331:NG-Nitroarginine Methyl Ester