Prolactin induced expression of interleukin-1 alpha, tumor necrosis factor-alpha, and transforming growth factor-alpha in cultured astrocytes.
Prolactin (PRL) is a potent mitogen in cultured astrocytes. Because one of the major effects of astrocyte proliferation is the expression of inflammatory cytokines, we examined the effect of PRL-induced mitogenesis on the expression of interleukin-1 (IL-1 alpha), tumor necrosis factor-alpha (TNF-alpha), and transforming growth factor-alpha (TGF-alpha) in cultured astrocytes. Astrocytes were stimulated with PRL or growth hormone (GH), and the expression of cytokines was determined by immunohistochemistry and Western blot analysis. Following incubation of astrocytes with 1 nM PRL for 6 h, strong positive staining of IL-1 alpha and TNF-alpha, but not TGF-alpha, was found. No detectable staining for the above cytokines was found in vehicle, or GH treated astrocytes. When astrocytes were incubated in the presence of 1 nM PRL for 18 h, strong positive staining for IL-1 alpha and TGF-alpha was found. Immunocytochemical analysis of the expression of TNF-alpha and IL-1 alpha in PRL stimulated astrocytes suggested that the expression of IL-1 alpha preceded the expression of TNF-alpha. To confirm this observation, Western blot analyses were performed on extracts from astrocytes incubated with 1 nM PRL in unstimulated astrocytes, IL-1 alpha levels were not detectable. In astrocytes stimulated with 1 nM PRL, expression of IL-1 alpha was clearly detected after 1 h of incubation, and IL-1 alpha levels continued to increase during the course of the experiment (6 h). In contrast, in astrocytes stimulated with 1 nM PRL, an increase in the expression of TNF-alpha was first apparent after 2 h of incubation.(ABSTRACT TRUNCATED AT 250 WORDS)
DeVito
W J
WJ
Division of Endocrinology, University of Massachusetts Medical Center, Worcester 10655, USA.
Avakian
C
C
Stone
S
S
Okulicz
W C
WC
Tang
K T
KT
Shamgochian
M
M
D000818:Animals; D001253:Astrocytes / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D001921:Brain / Q000166:cytology / Q000378:metabolism*; D002455:Cell Division / Q000187:drug effects; D002478:Cells, Cultured; D004305:Dose-Response Relationship, Drug; D005260:Female; D005904:Glial Fibrillary Acidic Protein / Q000032:analysis; D013006:Growth Hormone / Q000494:pharmacology; D007150:Immunohistochemistry; D007375:Interleukin-1 / Q000032:analysis / Q000096:biosynthesis*; D007700:Kinetics; D011388:Prolactin / Q000494:pharmacology*; D051381:Rats; D013997:Time Factors; D016211:Transforming Growth Factor alpha / Q000032:analysis / Q000096:biosynthesis*; D014409:Tumor Necrosis Factor-alpha / Q000032:analysis / Q000096:biosynthesis*
D005904:Glial Fibrillary Acidic Protein; D007375:Interleukin-1; D016211:Transforming Growth Factor alpha; D014409:Tumor Necrosis Factor-alpha; D011388:Prolactin; D013006:Growth Hormone