Effect of nitric oxide on prolactin secretion and hypothalamic biogenic amine contents.
Involvement of nitric oxide (NO) in the episodic secretion of prolactin was studied in conscious freely moving adult rats. Prolactin secretion was pulsatile in all animals of either group during the bleeding period (from 10:30 h to 13:30 h). Administration of N(omega)-nitro-L-arginine methyl ester (L-NAME), a NO synthase inhibitor, increased mean plasma levels of prolactin, and the absolute amplitude of prolactin peaks during the whole bleeding period as compared to values found in the control group. L-NAME increased norepinephrine (170%), dopamine (58.27%) and serotonin contents (30%) in the anterior hypothalamus. In the median eminence, dopamine and serotonin contents decreased (19.79% and 33.9% respectively) after L-NAME as compared to the values found in controls. In addition, norepinephrine content increased in mediobasal hypothalamus (79.6%) of rats treated with L-NAME. The results indicate that changes in NO production may modify the episodic secretion of prolactin. These effects were associated with changes in hypothalamic and median eminence biogenic amines.
Lafuente
Anunciación
A
Laboratorio de Toxicología, Facultad de Ciencias, Universidad de Vigo, Campus de Orense, Las Lagunas, 32004 Orense, Spain. lafuente@uvigo.es
González-Carracedo
Aníbal
A
Romero
Alejandro
A
Cano
Pilar
P
Esquifino
Ana I
AI
D000818:Animals; D001679:Biogenic Amines / Q000378:metabolism*; D004791:Enzyme Inhibitors / Q000378:metabolism; D007031:Hypothalamus / Q000737:chemistry* / Q000378:metabolism*; D008297:Male; D019331:NG-Nitroarginine Methyl Ester / Q000378:metabolism; D009569:Nitric Oxide / Q000378:metabolism*; D010507:Periodicity; D011388:Prolactin / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley
D001679:Biogenic Amines; D004791:Enzyme Inhibitors; D009569:Nitric Oxide; D011388:Prolactin; D019331:NG-Nitroarginine Methyl Ester