Effect of lipopolysaccharide on tumor necrosis factor and prolactin release from rat anterior pituitary cells.
TNF-alpha plays a critical role in the cascade of neuroendocrine events during inflammation and septic shock. It also affects the release of pituitary hormones and acts as a growth factor in immune and nonimmune cells. The aim of the present study was to investigate the release of TNF-alpha from rat anterior pituitary cells and the effect of the steroid medium on its release. Cultured anterior pituitary cells from lactating rats spontaneously released TNF-alpha. The presence of lipopolysaccharide (LPS, 0.1 microg/mL) in the culture medium significantly increased TNF-alpha release and inhibited prolactin release. Chronic estrogenization of ovariectomized rats or the presence of 17 beta-estradiol in the culture medium also increased TNF-alpha release. LPS significantly stimulated TNF-alpha release in all groups and abrogated the estrogen-induced prolactin release. We also investigated the effect of TNF-alpha on prolactin release. The presence of TNF-alpha (50 ng/mL) in the culture medium inhibited prolactin release from anterior pituitary cells. These data show that anterior pituitary cells in culture release TNF-alpha and that this release is stimulated by estrogens. Our results also indicate that LPS inhibits prolactin release in an estrogenic environment, suggesting that TNF-alpha could affect pituitary hormone release during endotoxemia.
Theas
M S
MS
Centro de Investigaciones en Reproducción, Facultad de Medicina, Universidad de Buenos Aires, Argentina.
De Laurentis
A
A
Lasaga
M
M
Pisera
D
D
Duvilanski
B H
BH
Seilcovich
A
A
D000818:Animals; D002478:Cells, Cultured; D004958:Estradiol / Q000494:pharmacology; D005260:Female; D007774:Lactation; D008070:Lipopolysaccharides / Q000494:pharmacology*; D010052:Ovariectomy; D010903:Pituitary Gland, Anterior / Q000187:drug effects / Q000378:metabolism*; D011388:Prolactin / Q000378:metabolism*; D051381:Rats; D017208:Rats, Wistar; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism*
D008070:Lipopolysaccharides; D014409:Tumor Necrosis Factor-alpha; D004958:Estradiol; D011388:Prolactin