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Effect of oxytocin on nitric oxide activity controlling gonadotropin secretion in humans
Author(s) -
Chiodera P.,
Volpi R.,
Manfredi G.,
Bortesi M. L.,
Capretti L.,
Magotti M. G.,
Saccanijotti G.,
Coiro V.
Publication year - 2003
Publication title -
european journal of clinical investigation
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.164
H-Index - 107
eISSN - 1365-2362
pISSN - 0014-2972
DOI - 10.1046/j.1365-2362.2003.01122.x
Subject(s) - endocrinology , medicine , luteinizing hormone , oxytocin , gonadotropin , nitric oxide , follicle stimulating hormone , hormone , nitric oxide synthase , secretion , chemistry , gonadotropin releasing hormone , bolus (digestion)
Background Previously described inhibitory effects of the nitric oxide synthase (NOS) inhibitor L‐NAME on luteinizing hormone‐releasing hormone (LH‐RH)‐induced LH and follicle stimulating hormone (FSH) secretion in humans suggested modulation by nitric oxide (NO) of the gonadotropin‐releasing action of LH‐RH. Design In order to establish whether oxytocin (OT) participates in this regulatory mechanism, 10 normal men were treated with LH‐RH (100 µg as an i.v. bolus) given alone or in the presence of L‐NAME (40 µg kg −1 injected plus 50 µg kg −1 infused i.v. for 60 min), OT (2 IU injected plus 4 IU infused i.v. for 60 min) or a combination of both drugs. Results The administration of OT was unable to change the gonadotropin responses to LH‐RH. In contrast, L‐NAME significantly reduced both FSH and LH increments induced by LH‐RH. When L‐NAME was given in the presence of OT, the LH and FSH responses to LH‐RH were similar to those observed after the administration of LH‐RH alone. Conclusion These data suggest antagonistic actions of OT and L‐NAME in the control of NOS activity in regulation of gonadotropin secretion induced by LH‐RH.