Prolactin modulation of nitric oxide and TNF-alpha production by peripheral neutrophils in rats.
It has been demonstrated that prolactin (PRL) is a potent immunomodulator that exerts stimulatory effects on physiological responses of immune cells. In the present research we have investigated whether PRL may influence nitric oxide (NO) and/or tumor necrosis factor-alpha (TNF-alpha) production in neutrophils obtained from inflammatory exudate of carrageenin-induced experimental pleurisy in the rat. In this acute model of inflammation the role of endogenous NO was evaluated using an inhibitor of NO-synthase, NG-nitro-L-arginine methyl ester (L-NAME). A treatment of animals with L-NAME (10 mg/kg s.c.) induced a reduction of volume and cell number of pleural exudate and a decrease of nitrite production (measured by the Griees reaction) by polymorphonuclear cells after 24 h of incubation, while D-NAME, the inactive isomer, was without effect. Neutrophils from ovine prolactin (oPRL) treated rats (5 mg/kg for 5 times s.c.) or from rats with a hyperprolactinaemia induced by pituitary gland graft produced higher amounts of NO both after 24 and 48 h of incubation. On the contrary, a clear reduction in the production of NO was found in neutrophils from rats treated with bromocriptine (BRC) (2 mg/kg s.c.), a dopamine D2-receptor agonist. TNF-alpha production (measured by MTT/cytotoxic assay) by neutrophils was markedly increased in PRL-treated or pituitary-grafted rats in comparison to controls, whereas BRC treatment reduced TNF-alpha production.
Meli
R
R
Department of Experimental Pharmacology, University of Naples Federico II, Italy.
Raso
G M
GM
Gualillo
O
O
Pacilio
M
M
Di Carlo
R
R
D000818:Animals; D005122:Exudates and Transudates / Q000378:metabolism; D008297:Male; D019331:NG-Nitroarginine Methyl Ester / Q000494:pharmacology; D009504:Neutrophils / Q000187:drug effects* / Q000378:metabolism; D009569:Nitric Oxide / Q000096:biosynthesis*; D011388:Prolactin / Q000097:blood / Q000502:physiology*; D051381:Rats; D017208:Rats, Wistar; D014409:Tumor Necrosis Factor-alpha / Q000096:biosynthesis*
D014409:Tumor Necrosis Factor-alpha; D009569:Nitric Oxide; D011388:Prolactin; D019331:NG-Nitroarginine Methyl Ester