Tumor necrosis factor-alpha stimulates prolactin release from anterior pituitary cells: a possible involvement of intracellular calcium mobilization.
We investigated the effects of tumor necrosis factor-alpha (TNF alpha), a cytokine produced as one aspect of inflammatory reactions, on the intracellular free calcium concentration in single pituitary cells using a calcium-sensitive fluorescent dye, indo-1, and a digital imaging fluorescence microscopic system. TNF alpha induced an increase in intracellular free calcium immediately after administration, reaching a peak after 30 sec and then returning to nearly the basal level after 120 sec in the pituitary cells. The cells responding to TNF alpha constitute about 15% of the pituitary cell population, and these cells never responded to the hypothalamic releasing hormones TRH, GnRH, GH-releasing hormone, or CRH. To define the role of calcium in TNF alpha-induced PRL release, dispersed pituitary cells were exposed to agents that modify TNF alpha-induced calcium mobilization. Such calcium channel blockers as cobalt and verapamil decreased basal and TNF alpha-induced PRL release. A low calcium medium also decreased TNF alpha-induced PRL release. These data suggest that intracellular calcium mobilization may be involved in the process of TNF alpha-induced PRL release.
Koike
K
K
Department of Obstetrics and Gynecology, Osaka University Medical School, Japan.
Masumoto
N
N
Kasahara
K
K
Yamaguchi
M
M
Tasaka
K
K
Hirota
K
K
Miyake
A
A
Tanizawa
O
O
D000818:Animals; D001692:Biological Transport; D002118:Calcium / Q000378:metabolism* / Q000502:physiology; D005260:Female; D007425:Intracellular Membranes / Q000378:metabolism*; D009994:Osmolar Concentration; D010903:Pituitary Gland, Anterior / Q000166:cytology / Q000378:metabolism*; D011388:Prolactin / Q000378:metabolism*; D051381:Rats; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology*
D014409:Tumor Necrosis Factor-alpha; D011388:Prolactin; D002118:Calcium