Suppressive effect of zearalenone, an estrogenic mycotoxin, on bovine neutrophil chemiluminescence.
The effects of zearalenone (ZEA), an estrogenic mycotoxin produced by Fusarium fungi, on bovine neutrophils were investigated in vitro using chemiluninescence, a bactericidal parameter. ZEA suppressed luminol-dependent, phorbol 12-myristate 13-acetate (PMA)-elicited chemiluminescence in a dose-dependent manner at concentrations of 10(-4) M and 10(-5) M. No significant suppression was observed at concentrations lower than 10(-6) M. The possible mode ofaction of 10(-4) M ZEA on the cell activity was investigated with special reference to intracellular Ca2+ ([Ca2+]i) release and estrogen receptors. The 10(-4) M ZEA treatment significantly impaired [Ca2+]i release. When pretreated with a low dose (10(-6) M) of PMA, the cells resisted the ZEA-induced chemiluminescence suppression. However, pretreatment of the cells with the estrogen receptor blockers Tamoxifen and ICl 182,780 (both at 10(-6) M) did not annul the suppressive ZEA action. Considering that PMA is an activator of protein kinase C (PKC), a signal transducing enzyme, and in association with a rise in [Ca2+]i causes cytosolic PKC to shift to the plasma membrane where the activated PKC triggers a varied array of cellular responses, the pharmacological dose of ZEA might have suppressed chemiluminescence by hindering the release of [Ca2+]i and the PKC shift. The results of pretreatment with estrogen receptor blockers, however, did not support the suggestion that the ZEA treatment affected the cells via estrogen receptor pathways.
Murata
H
H
Department of Safety Research, National Institute of Animal Health, Tsukuba, Ibaraki, Japan.
Shimada
N
N
Yoshioka
M
M
D000818:Animals; D002118:Calcium / Q000493:pharmacokinetics; D002417:Cattle; D018929:Cell Culture Techniques; D004305:Dose-Response Relationship, Drug; D004968:Estrogens, Non-Steroidal / Q000494:pharmacology*; D005260:Female; D008163:Luminescent Measurements; D009504:Neutrophils / Q000187:drug effects* / Q000502:physiology; D011960:Receptors, Estrogen / Q000187:drug effects / Q000502:physiology; D015398:Signal Transduction; D015025:Zearalenone / Q000494:pharmacology*
D004968:Estrogens, Non-Steroidal; D011960:Receptors, Estrogen; D015025:Zearalenone; D002118:Calcium