The effects of L-arginine on the release of prolactin from decidual explants in vitro.
OBJECTIVE
Our aim was to elucidate a role for the L -arginine-nitric oxide-cyclic guanosine monophosphate pathway in the control of decidual prolactin release in vitro.


METHODS
In decidua obtained from normal vaginal deliveries, we examined the effects of L -arginine; a stable analog of cyclic guanosine monophosphate, 8-bromo-cyclic guanosine monophosphate; and two nitric oxide synthase inhibitors, L -nitro arginine methyl ester (L -NAME) and L -nitro monomethyl arginine (L -NMMA) on the release of prolactin from decidual tissue in vitro.


RESULTS
L -arginine, at 100 micromol/L, produced an increase in medium prolactin concentration after a 2-hour exposure; however, its inactive isomer, D -arginine, at the same concentration, did not. The increase in prolactin release initiated by L -arginine was sustained after a 24-hour incubation. In addition, 8-bromo-cyclic guanosine monophosphate (10 micromol/L) stimulated prolactin release. At 2 hours, the effects of L -arginine were reversed by L -NAME (100 micromol/L), which by itself was without effect. Incubation of tissue with L -NAME for 24 hours inhibited prolactin secretion (24 hours; P <.05, vs control); however, L -NMMA was without effect.


CONCLUSIONS
These results suggest that the L -arginine-nitric oxide-cyclic guanosine monophosphate pathway is involved in the regulation of prolactin secretion by decidual tissue.
Kumari
M
M
Division of Maternal-Fetal Medicine, Department of Obstetrics and Gynecology, Brigham and Women's Hospital and Harvard Medical School, Boston, MA, USA.
Heffner
L J
LJ
D001120:Arginine / Q000494:pharmacology*; D006152:Cyclic GMP / Q000031:analogs & derivatives / Q000494:pharmacology; D003656:Decidua / Q000187:drug effects* / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D005260:Female; D006801:Humans; D066298:In Vitro Techniques; D019331:NG-Nitroarginine Methyl Ester / Q000494:pharmacology; D009569:Nitric Oxide / Q000378:metabolism; D011247:Pregnancy; D011388:Prolactin / Q000378:metabolism*
C016276:8-bromocyclic GMP; D009569:Nitric Oxide; D011388:Prolactin; D001120:Arginine; D006152:Cyclic GMP; D019331:NG-Nitroarginine Methyl Ester